cave
noun
°A large, naturally-occurring cavity formed underground, or in the face of a cliff or a hillside.
"We found a cave on the mountainside where we could take shelter."
°A hole, depression, or gap in earth or rock, whether natural or man-made.
verb
°To surrender.
"He caved under pressure."
°To collapse.
"First the braces buckled, then the roof began to cave, then we ran."
interjection
°(British public school slang) look out!; beware!