a sum of money so large as to be considered unreal
2.
counterfeit money
3. derogatory
foreign currency
funny money in American English
US
Informal
1.
bills, vouchers, etc. resembling or used as a substitute for legal currency
2.
money that is illegal or that is tainted by illegal activity; specif., counterfeit money
3.
currency, securities, etc. regarded as being of uncertain or decreasing value, as because of inflationary fiscal policy, highly leveraged financing, etc.