Wiktionary
deer in the headlights
n. 1 (context idiomatic English) A mental state of high arousal caused by anxiety fear, panic, surprise and/or confusion, or substance abuse. 2 (context idiomatic English) A stunned or glazed expression.
Usage examples of "deer in the headlights".
Fame and fortune, without being the deer in the headlights, that was what she wanted.
All around them were men and women wearing that same blank look, men and women frozen like a herd of deer in the headlights of an oncoming truck.
When the car came around the bend, he was right in the middle of the road, standing there like a deer in the headlights, and surely the driver must see him.