burst vs cave in

burst and cave in both are nouns.

Word	Noun	Adjective	Verb	Adverb
burst	Yes	No	Yes	No
cave in	Yes	No	Yes	No

burst (noun)	cave in (noun)
the act of exploding or bursting	the sudden collapse of something into a hollow beneath it
rapid simultaneous discharge of firearms
a sudden flurry of activity (often for no obvious reason)
a sudden intense happening

burst (verb)	cave in (verb)
come open suddenly and violently, as if from internal pressure	break down, literally or metaphorically
break open or apart suddenly and forcefully
emerge suddenly
burst outward, usually with noise
force out or release suddenly and often violently something pent up
move suddenly, energetically, or violently
cause to burst
be in a state of movement or action