fight (v.) Look up fight at Dictionary.com
Old English feohtan "to combat, contend with weapons, strive; attack; gain by fighting, win" (intransitive; class III strong verb; past tense feaht, past participle fohten), from Proto-Germanic *fehtan (cognates: Old High German fehtan, German fechten, Middle Dutch and Dutch vechten, Old Frisian fiuhta "to fight"), from PIE *pek- (2) "to pluck out" (wool or hair), apparently with a notion of "pulling roughly" (cognates: Greek pekein "to comb, shear," pekos "fleece, wool;" Persian pashm "wool, down," Latin pectere "to comb," Sanskrit paksman- "eyebrows, hair").

Spelling substitution of -gh- for a "hard H" sound was a Middle English scribal habit, especially before -t-. In some late Old English examples, the middle consonant was represented by a yogh. Among provincial early Modern English spellings, Wright lists faight, fate, fecht, feeght, feight, feit, feyght, feyt, feort, foight.

From c.1200 as "offer resistance, struggle;" also "to quarrel, wrangle, create a disturbance." From late 14c. as "be in conflict." Transitive use from 1690s. To fight for "contest on behalf of" is from early 14c. To fight back "resist" is recorded from 1890. Well figt þat wel fligt ("he fights well that flies fast") was a Middle English proverb.
fight (n.) Look up fight at Dictionary.com
Old English feohte, gefeoht "a fight, combat, hostile encounter;" see fight (v.). Compare Old Frisian fiucht, Old Saxon fehta, Dutch gevecht, Old High German gifeht, German Gefecht. Meaning "power or inclination to fight" is from 1812.