Bogus currency. Forged or sham bills. Bogus transactions. Fraudulent transactions. The word is by some connected with bogie.
Lowell (Biglow Papers) says, “I more than suspect the world to be a corruption of the French bagasse. ” In French argot is another word (bogue), the rind of a green chestnut, or case of a watch; a bogus chestnut or watch.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894