put the finger on

Idioms  

1. Inform on, as in The witness put the finger on the defendant. [Slang; c. 1920] Also see put one's finger on.

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Example Sentences

"It is hard to put the finger on," he replied to an opening question, like a mechanic mystified by a misfiring car engine.

From BBC

Stressing that racial equity programs benefit the entire population, Rice added that Biden “put the finger on the chest of everybody in his administration to be with the program. … While this is the moral thing to do and the right thing to do, it’s also the smart thing to do if we’re going to increase economic growth and create jobs.”

From Washington Post

There's a lot going on, but no one can quite put the finger on it.

From Salon

On removing this some weeks later, he discovered he had put the finger on the wrong way round.

From The Guardian

The big philosophical number for Sonny, the shooter who becomes a father figure to Calogero after the kid doesn’t put the finger on him, is a bald homage to Bobby Darin’s finger-snappin’ lounge version of “Mack the Knife.”

From Washington Post