watch out

Related to watch out: look out

watch out

To pay attention (usually because danger is imminent). Often used as an imperative. You need to watch out for all these cords—they're a serious tripping hazard. Watch out! There's a car coming!
See also: out, watch
Farlex Dictionary of Idioms.

watch out

v.
1. To be careful or on the alert; take care: If you don't watch out, you'll fall on the ice.
2. watch out for To be careful of some danger: Watch out for falling rocks!
See also: out, watch
The American Heritage® Dictionary of Phrasal Verbs.
See also:
  • on the bird
  • keep good time
  • What time have you got?
  • on someone’s watch
  • keep (close) watch for (someone or something)
  • watch it
  • Watch it!
  • flop
  • keep a close eye/watch on somebody/something
  • keep watch on