keep_one's_eyes_open
1. [ verb ] pay attention; be watchful;(colloquial)
Synonyms: keep_one's_eyes_skinned keep_one's_eyes_peeled
Examples:

: "Keep your eyes peeled for any policemen"

Related terms: watch colloquialism
Similar spelling:   keep_one's_eyes_off
  keep_one's_eyes_peeled
  keep_one's_eyes_skinned
  keep_one's_hands_off
  keep_one's_distance