keep cave

keep cave

old-fashioned To remain vigilant or carefully watchful (for something or someone); to act as a guard or watch. In this phrase, "cave" derives from a Latin word meaning "beware." The gang employed youths from the area to keep cave and give a signal if any police officers arrived. I offered to keep cave at the door, as I had no intention of risking my life in that creepy old house.
See also: cave, keep
Farlex Dictionary of Idioms.

keep cave

act as lookout. school slang
Cave is a Latin word meaning ‘beware!’ Pronounced as one or two syllables, cave was the traditional warning uttered by a schoolchild to let others know that a teacher was approaching.
See also: cave, keep
Farlex Partner Idioms Dictionary
See also:
  • keep nit
  • nit
  • have an eye out
  • keep an eye out
  • rip
  • have (one's)/an eye out for (someone or something)
  • rest in peace
  • keep eye out
  • keep (one's) eye(s) out (for something or someone)
  • keep an eye out for (someone or something)