break down vs burn out

break down and burn out both are verbs.

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

As verbs, burn out is a hyponym of break down; that is, burn out is a word with a more specific, narrower meaning than break down:

Other hyponyms of break down include crash, go down, blow, blow out, misfire, malfunction, misfunction.

break down (verb)	burn out (verb)
collapse due to fatigue, an illness, or a sudden attack	melt, break, or become otherwise unusable
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