decease vs break down

decease is a noun but break down is not a noun.

Word	Noun	Adjective	Verb	Adverb
decease	Yes	No	Yes	No
break down	No	No	Yes	No

decease (noun)	break down (noun)
the event of dying or departure from life

decease (verb)	break down (verb)
pass from physical life and lose all bodily attributes and functions necessary to sustain life	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