put someone to the acid test—submit smb. to a crucial test that will show his qualities:
- His words hit me with a jolt of truth, and after listening to him speak, I decided to put him to the acid test.
put the acid on someone—(Austral., NZ sl.) exert pressure on a person (to obtain a loan, favor, etc.):
- They want to shift the ship at seven. That puts the acid on us.