burn out vs break down

burn out and break down both are verbs.

Word	Noun	Adjective	Verb	Adverb
burn out	No	No	Yes	No
break down	No	No	Yes	No

As verbs, break down is a hypernym of burn out; that is, break down is a word with a broader meaning than burn out:

Other hypernyms of burn out include break, conk out, die, fail, give out, give way, go, go bad.

burn out (verb)	break down (verb)
melt, break, or become otherwise unusable	collapse due to fatigue, an illness, or a sudden attack
	stop operating or functioning
	separate (substances) into constituent elements or parts
	make a mathematical, chemical, or grammatical analysis of; break down into components or essential features
	make ineffective
	cause to fall or collapse
	lose control of one's emotions
	fall apart