funny money

noun

Slang.

1. counterfeit currency.

2. money from undisclosed or questionable sources.

3. currency of little value, as of a nation whose currency has been artificially inflated or recently devaluated.

4. any foreign currency.

funny money

noun

1. a sum of money so large as to be considered unreal

2. counterfeit money

3. derogatory,  foreign currency

Word History and Origins

Origin of funny money¹

First recorded in 1940–45

Idioms and Phrases

Counterfeit money; also, money from an obscure or questionable source. For example, The police warned storekeepers that some funny money was being passed around town. This expression probably endures because of its rhyme. [1930s]