decompose vs decay

decompose is not a noun while decay is a noun.

Word	Noun	Adjective	Verb	Adverb
decompose	No	No	Yes	No
decay	Yes	No	Yes	No

As verbs, decay is a hypernym of decompose; that is, decay is a word with a broader meaning than decompose:

As verbs, decompose and decay are synonyms defined as:

Other synonyms of decompose include disintegrate.

decompose (noun)	decay (noun)
	the organic phenomenon of rotting
	a gradual decrease; as of stored charge or current
	the process of gradually becoming inferior
	the spontaneous disintegration of a radioactive substance along with the emission of ionizing radiation
	an inferior state resulting from the process of decaying

decompose (verb)	decay (verb)
separate (substances) into constituent elements or parts	fall into decay or ruin
break down	lose a stored charge, magnetic flux, or current
lose a stored charge, magnetic flux, or current	undergo decay or decomposition