ladder vs fall apart

ladder is a noun but fall apart is not a noun.

Word	Noun	Adjective	Verb	Adverb
ladder	Yes	No	Yes	No
fall apart	No	No	Yes	No

As verbs, fall apart is a hypernym of ladder; that is, fall apart is a word with a broader meaning than ladder:

Other hypernyms of ladder include break, come apart, separate, split up.

ladder (noun)	fall apart (noun)
steps consisting of two parallel members connected by rungs; for climbing up or down
a row of unravelled stitches
ascending stages by which somebody or something can progress

ladder (verb)	fall apart (verb)
come unraveled or undone as if by snagging	become separated into pieces or fragments
	break or fall apart into fragments
	go to pieces
	lose one's emotional or mental composure