do something on sight

on sight

As soon as someone or something is or can be seen. Police have orders to shoot the suspect on sight.
See also: on, sight
Farlex Dictionary of Idioms.

do something on ˈsight

do or feel something as soon as you see somebody/something: She complained constantly about the hotel, which she hated on sight. The soldiers were ordered to shoot on sight.
See also: on, sight, something
Farlex Partner Idioms Dictionary
See also:
  • on sight
  • a sight
  • a heap sight
  • heap sight
  • come into sight
  • be (with)in sight
  • be in/within sight
  • burst into sight
  • in sight
  • sight