not put (one's) finger on (something)

not put (one's) finger on (something)

To be unable to recall fully, clearly, or correctly. I can't put my finger on what this is reminding me of. There's something I was supposed to do this afternoon, but I can't put my finger on it.
See also: finger, not, on, put

not put your ˈfinger on something

(informal) not be able to say exactly what is wrong or different about a particular situation: I knew something she had said wasn’t true, but I couldn’t quite put my finger on it.There’s something wrong with these statistics but I just can’t put my finger on what it is.
See also: finger, not, on, put, something