felon (n.) Look up felon at Dictionary.com
late 13c., from Old French felon "evil-doer, scoundrel, traitor, rebel, the Devil" (9c.), from Medieval Latin fellonem (nominative fello) "evil-doer," of uncertain origin, perhaps from Frankish *fillo, *filljo "person who whips or beats, scourger" (source of Old High German fillen "to whip"); or from Latin fel "gall, poison," on the notion of "one full of bitterness."

Another theory (advanced by Professor R. Atkinson of Dublin) traces it to Latin fellare "to suck" (see fecund), which had an obscene secondary meaning in classical Latin (well-known to readers of Martial and Catullus), which would make a felon etymologically a "cock-sucker." OED inclines toward the "gall" explanation, but finds Atkinson's "most plausible" of the others.
felonious (adj.) Look up felonious at Dictionary.com
mid-15c. (implied in feloniously), from felony + -ous. Replaced felonous (mid-14c.) by c.1600. Felonly (c.1300) was another variation.
felony (n.) Look up felony at Dictionary.com
late 13c. as a term in common law, in Anglo-French, from Old French felonie (12c.) "wickedness, evil, treachery, perfidy, crime, cruelty, sin," from Gallo-Roman *fellonia, from fellonem (see felon).
felsic (adj.) Look up felsic at Dictionary.com
1912, from feldspar + silica + -ic.
felt (n.) Look up felt at Dictionary.com
Old English felt, from West Germanic *feltaz "something beaten, compressed wool" (cognates: Old Saxon filt, Middle Dutch vilt, Old High German filz, German Filz, Danish filt), from Proto-Germanic *felt- "to beat," from PIE *pel- (6) "to thrust, strike, drive" (source also of Old Church Slavonic plusti), with a sense of "beating" (see pulse (n.1)).
felt (v.1) Look up felt at Dictionary.com
"to make into felt," early 14c. (implied in felted); see felt (n.).
felt (v.2) Look up felt at Dictionary.com
past tense and past participle of feel (v.).
fem (n.) Look up fem at Dictionary.com
slang for "woman," by 1936, from female.
female (n.) Look up female at Dictionary.com
early 14c., from Old French femelle (12c.) "woman, female," from Medieval Latin femella "a female," from Latin femella "young female, girl," diminutive of femina "woman" (see feminine).

Sense extended in Vulgar Latin from humans to female of other animals. Spelling altered late 14c. on mistaken parallel of male. As an adjective, from early 14c. Reference to sockets, etc., is from 1660s.
femaleness (n.) Look up femaleness at Dictionary.com
1889, from female + -ness.
feme covert (n.) Look up feme covert at Dictionary.com
"married woman" (legalese), c.1600, French, from Old French feme coverte, second element fem. of covert "covered." Contrasted to feme sole.
feminine (adj.) Look up feminine at Dictionary.com
mid-14c., "of the female sex," from Old French femenin (12c.) "feminine, female; with feminine qualities, effeminate," from Latin femininus "feminine" (in the grammatical sense at first), from femina "woman, female," literally "she who suckles," from root of felare "to suck, suckle" (see fecund). Sense of "woman-like, proper to or characteristic of women" is recorded from mid-15c.

The interplay of meanings now represented in female, feminine, and effeminate, and the attempt to make them clear and separate, has led to many coinages: feminitude (1878); feminile "feminine" (1640s); feminility "womanliness" (1838); femality (17c., "effeminacy;" 1754 "female nature"). Also feminality (1640s, "quality or state of being female"), from rare adjective feminal (late 14c.), from Old French feminal. And femineity "quality or state of being feminine," from Latin femineus "of a woman, pertaining to a woman."
femininity (n.) Look up femininity at Dictionary.com
late 14c., femynynytee, from feminine + -ity.
feminism (n.) Look up feminism at Dictionary.com
1851, "state of being feminine;" sense of "advocacy of women's rights" is 1895, from French féminisme (1837); see feminine + -ism.
feminist (n.) Look up feminist at Dictionary.com
1893, from French féministe (1872); also see feminism. As an adjective by 1897. Womanist sometimes was tried as a native alternative.
feminity (n.) Look up feminity at Dictionary.com
"quality or state of being feminine," late 14c., from Old French feminité, from Latin femina (see feminine).
feminization (n.) Look up feminization at Dictionary.com
1844, noun of action from feminize.
feminize (v.) Look up feminize at Dictionary.com
1650s, from Latin femina (see feminine) + -ize. Related: Feminized; feminizing. Femalize (1670s, intransitive, 1709, transitive) and femininize (1868) are more rare.
femme (n.) Look up femme at Dictionary.com
French, literally "woman," from Old French feme, from Latin femina (see feminine). Slang meaning "passive and more feminine partner in a lesbian couple" attested by 1961.
femme fatale (n.) Look up femme fatale at Dictionary.com
"attractive and dangerous woman," 1895, from French femme fatale, attested by 1844, from French femme "woman," from Latin femina (see feminine) + fatale (see fatal).
Une femme fatale est une femme qui porte malheur. [Jules Claretie, "La Vie a Paris," 1896]
Earlier, such a woman might be called a Circe.
femoral (adj.) Look up femoral at Dictionary.com
1782, from Latin femoris, genitive of femur "thigh" (see femur) + -al (1).
femur (n.) Look up femur at Dictionary.com
1560s, from Latin femur "thigh," of unknown origin; borrowed first as an architectural term, 1799 as "thighbone."
fen (n.) Look up fen at Dictionary.com
Old English fenn "mud, mire, dirt; fen, marsh, moor," from Proto-Germanic *fanjam- (cognates: Old Saxon feni, Old Frisian fenne, Middle Dutch venne, Dutch veen, Old High German fenna, German Fenn "marsh," Old Norse fen, Gothic fani "mud"), from PIE *pen- "swamp" (cognates: Gaulish anam "water," Sanskrit pankah "bog, marsh, mud," Old Prussian pannean "swampland"). Italian and Spanish fango, Old French fanc, French fange "mud" are loan-words from Germanic. The native Latin word was limus or lutum.
fence (n.) Look up fence at Dictionary.com
early 14c., "action of defending," shortening of defens (see defense). Spelling alternated between -c- and -s- in Middle English. Sense of "enclosure" is first recorded mid-15c. on notion of "that which serves as a defense." Sense of "dealer in stolen goods" is thieves' slang, first attested c.1700, from notion of such transactions taking place under defense of secrecy. To be figuratively on the fence "uncommitted" is from 1828, perhaps from the notion of spectators at a fight, or a simple literal image: "A man sitting on the top of a fence, can jump down on either side with equal facility." [Bartlett, "Dictionary of Americanisms," 1848].
fence (v.) Look up fence at Dictionary.com
mid-15c., "surround with a fence;" c.1500, "defend, screen, protect;" 1590s, "fight with swords;" the last from the noun in this sense (1530s); see fence (n.). Related: Fenced, fencing.
fencible (adj.) Look up fencible at Dictionary.com
early 14c., "capable of making a defense," short for defensible; see fence (n.) + -ible.
fencing (n.) Look up fencing at Dictionary.com
mid-15c., "defending, act of protecting;" 1580s in the sword-fighting sense; noun from present participle of fence (v.). In spite of the re-enactment in 1285 of the Assize of Arms of 1181, fencing was regarded as unlawful in England. The keeping of fencing schools was forbidden in the City of London, "as fools who delight in mischief do learn to fence with buckler, and thereby are encouraged in their follies." Meaning "putting up fences" is from 1620s; that of "an enclosure" is from 1580s; meaning "receiving stolen goods" is from 1851 (see fence (n.)); meaning "materials for an enclosure" is from 1856.
fend (v.) Look up fend at Dictionary.com
late 13c., shortening of defend. To fend for oneself (1620s) is to see to one's own defense. Related: Fended; fending.
fender (n.) Look up fender at Dictionary.com
late 13c., shortening of defender. Used of attachments to boats at first, of fireplaces since 1680s; application to automobiles is 1919.
fenestration (n.) Look up fenestration at Dictionary.com
1870 in the anatomical sense, noun of action from Latin fenestrare, from fenestra "window, opening for light," perhaps from Etruscan. Meaning "arrangement of windows" is from 1846. Related: Fenestrated.
feng shui (n.) Look up feng shui at Dictionary.com
also feng-shui, 1797, from Chinese, from feng "wind" + shui "water." A system of spiritual influences in natural landscapes and a means of regulating them.
Fenian Look up Fenian at Dictionary.com
1816, blend of Old Irish feinne, plural of fiann, name of a band of Irish warriors + Old Irish Fene, name of the ancient inhabitants of Ireland. Reference to Irish-American brotherhood of that name first attested 1864.
fennec (n.) Look up fennec at Dictionary.com
fox-like animal of Africa, 1790, from Arabic fenek, fanak "a name vaguely applied to various fur-bearing animals" [OED].
fennel (n.) Look up fennel at Dictionary.com
Old English fenol, finul, perhaps via (or influenced by) Old French fenoil or directly from Vulgar Latin fenuculum, from Latin feniculum, diminutive of fenum, faenum "hay," probably literally "produce" (see fecund). Apparently so called from its hay-like appearance and sweet odor.
fenugreek (n.) Look up fenugreek at Dictionary.com
Old English fenograecum, from Latin faenugraecum, literally "Greek hay," from faenum (see fennel) + Graecum. The modern form in English is from Middle French fenugrec.
fer de lance (n.) Look up fer de lance at Dictionary.com
large poisonous snake of American tropics, 1880, from French, "lance-head," literally "iron of a lance." So called for its shape.
feral (adj.) Look up feral at Dictionary.com
c.1600, from Middle French feral "wild," from Latin fera, in phrase fera bestia "wild animal," from ferus "wild" (see fierce).
Ferdinand Look up Ferdinand at Dictionary.com
masc. proper name, of Germanic origin, first element perhaps Proto-Germanic *farthi, abstract noun from root *far- "to fare, travel" (see fare (v.)); second element perhaps related to Old English neðan, Old High German nendan "to risk, venture."
fere (n.) Look up fere at Dictionary.com
"companion" (obsolete), from Middle English fere, a shortening of Old English gefera "associate, comrade, fellow-disciple; wife, man, servant," from root of faran "to go, travel" (see fare (v.)). Compare German Gefährte "companion," from the same root.
Fergus Look up Fergus at Dictionary.com
masc. proper name, from Gaelic Fearghus or Old Irish Fergus "man-ability," first element cognate with Latin vir "man," second from Old Irish gus "ability, excellence, strength, inclination," from Celtic root *gustu- "choice," from PIE root *geus- "to taste" (see gusto).
ferhoodle (v.) Look up ferhoodle at Dictionary.com
"to confuse, perplex," from Pennsylvania German verhuddle "to confuse, tangle," related to German verhudeln "to bungle, botch." Related: Ferhoodled; ferhoodling.
ferial (adj.) Look up ferial at Dictionary.com
"pertaining to holidays," late 14c., from Old French ferial, from Medieval Latin ferialis, from Latin feriae (see feast (n.)).
ferine (adj.) Look up ferine at Dictionary.com
1630s, from Latin ferinus "pertaining to wild animals," from fera "wild beast" (see fierce).
Feringhee (n.) Look up Feringhee at Dictionary.com
name used in India for "European," 1630s, from Persian Farangi, from Arabic Faranji (10c.), from Old French Franc "Frank" (see Frank) + Arabic ethnic suffix -i. The fr- sound is not possible in Arabic.
fermata (n.) Look up fermata at Dictionary.com
1876, musical term, Italian, literally "stop, pause," from fermare "to fasten, to stop," from fermo "strong, fastened," from Latin firmus (see firm (adj.)).
ferment (v.) Look up ferment at Dictionary.com
late 14c., from Old French fermenter (13c.) and directly from Latin fermentare "to leaven, ferment," from fermentum "substance causing fermentation, leaven," from root of fervere "to boil, seethe" (see brew). Figurative use from 1650s. Related: Fermented; fermenting.
ferment (n.) Look up ferment at Dictionary.com
early 15c., from Middle French ferment, from Latin fermentum (see ferment (v.)). Figurative sense of "anger, passion" is from 1670s.
fermentation (n.) Look up fermentation at Dictionary.com
late 14c., in alchemy, with a broad sense; modern scientific sense is from c.1600; from Late Latin fermentationem (nominative fermentatio), noun of action from fermentare (see ferment (v.)). Figurative use attested from 1650s.
Fermium (n.) Look up Fermium at Dictionary.com
discovered in the debris of a 1952 U.S. nuclear test in the Pacific, named 1955 for Italian-born U.S. physicist Enrico Fermi (1901-1954).
fern (n.) Look up fern at Dictionary.com
Old English fearn, from Proto-Germanic *farno- (cognates: Old Saxon farn, Middle Dutch vaern, Dutch varen, Old High German farn, German Farn), possibly with a sense of "having feathery fronds" and from PIE *por-no-, a root which has yielded words for "feather, wing" (cognates: Sanskrit parnam "feather;" Lithuanian papartis "fern;" Russian paporot'; Greek pteris "fern," pteron "feather"), from root *per- (see petition (n.)). The plant's ability to appear as if from nothing accounts for the ancient belief that fern seeds conferred invisibility.