stone-broke vs bust

stone-broke is not a noun while bust is a noun.

Word	Noun	Adjective	Verb	Adverb
stone-broke	No	Yes	No	No
bust	Yes	Yes	Yes	No

As adjectives, stone-broke and bust are synonyms defined as:

Other synonyms of stone-broke include broke, skint, stony-broke.

stone-broke (noun)	bust (noun)
	an occasion for excessive eating or drinking
	a sculpture of the head and shoulders of a person
	the chest of a woman
	a complete failure

stone-broke (adjective)	bust (adjective)
lacking funds	lacking funds

stone-broke (verb)	bust (verb)
	break open or apart suddenly and forcefully
	go to pieces
	ruin completely
	separate or cause to separate abruptly
	search without warning, make a sudden surprise attack on