"get dishonestly or deviously," 1926, American English, possibly a variant of English dialectal fainaigue "to cheat or renege" (at cards), which is of unknown origin. Liberman says finagle is from figgle, phonetic variant of fiddle "fidget about," frequentative of fig. Related: Finagled; finagling.[finagle etymology, finagle origin, 英语词源]