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.

on sight

Also, at sight. Immediately upon seeing, as in The soldiers threatened to shoot looters on sight, or He's able to multiply those three-digit figures at sight. [Second half of 1400s]
See also: on, sight
The American Heritage® Dictionary of Idioms by Christine Ammer.

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

on sight

Immediately upon being seen: threatened to shoot looters on sight.
See also: on, sight
American Heritage® Dictionary of the English Language, Fifth Edition.
See also:
  • do something on sight
  • a sight
  • heap sight
  • a heap sight
  • come into sight
  • be (with)in sight
  • be in/within sight
  • burst into sight
  • in sight
  • sight