The story
Unknown. Sayers (2014) suggests a derivation from Irish ceartaithe (“corrected, set straight”, old spelling ceartuighthe), the past participle of ceartaigh. The OED references Fitzedward Hall's tentative query in Modern English (1873) of French colifichet (“trinket, bauble”), and F. C. Birkbeck Terry more fancifully proposes a corruption of "quaerite, which is it?" Compare also Scottish English carritch, a corruption of catechism.
Etymology from Wiktionary, CC BY-SA 4.0.