put (your) finger on (something)

to discover the exact reason why a situation is the way it is, especially when something is wrong.

I know there's something wrong, but I can't put my finger on exactly what it is. (often negative)

I think you've just put your finger on the biggest problem facing the Conservative party in this election.

• can't see past the end of nose
• can't see past the end of your nose
• can't see the wood for the trees
• can't stand the pace
• can't take eyes off
• can't take eyes off someone
• can't take eyes off something
• can't take the pace
• can't take your eyes off
• can't take your eyes off someone
• can't take your eyes off something
• can't tell arse from elbow
• can't tell arse from your elbow
• can't tell your arse from elbow
• can't tell your arse from your elbow
• can't think straight
• can't to save life
• can't to save your life
• cap it all
• cap off
• cap something off
• carbon copy
• cardboard city
• cards are stacked against
• cards are stacked against someone