slide down vs collapse

slide down is not a noun while collapse is a noun.

Word	Noun	Adjective	Verb	Adverb
slide down	No	No	Yes	No
collapse	Yes	No	Yes	No

As verbs, collapse is a hypernym of slide down; that is, collapse is a word with a broader meaning than slide down:

Other hypernyms of slide down include break, cave in, fall in, founder, give, give way.

slide down (noun)	collapse (noun)
	the act of throwing yourself down; collapse; sink
	a natural event caused by something suddenly falling down or caving in
	a sudden large decline of business or the prices of stocks (especially one that causes additional failures)
	an abrupt failure of function or complete physical exhaustion

slide down (verb)	collapse (verb)
fall or sink heavily	collapse due to fatigue, an illness, or a sudden attack
	lose significance, effectiveness, or value
	suffer a nervous breakdown
	break down, literally or metaphorically
	fold or close up
	fall apart
	cause to burst