- fault (n.)
- late 13c., faute, "deficiency," from Old French faute (12c.) "opening, gap; failure, flaw, blemish; lack, deficiency," from Vulgar Latin *fallita "a shortcoming, falling," noun use of fem. past participle, from Latin falsus "deceptive, feigned, spurious," past participle of fallere "deceive, disappoint" (see fail).
The -l- was restored 16c., probably in imitation of Latin, but was not pronounced till 18c. Sense of "physical defect" is from early 14c.; that of "moral culpability" is first recorded late 14c. Geological sense is from 1796. The use in tennis (c.1600) is closer to the etymological sense. - fault (v.)
- late 14c., Scottish, "be deficient;" see fault (n.). Meaning "find fault with" is from mid-15c. Related: Faulted; faulter; faulting.