dilapidation vs decay

dilapidation and decay both are nouns.

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

As nouns, decay is a hypernym of dilapidation; that is, decay is a word with a broader meaning than dilapidation:

dilapidation (noun)	decay (noun)
the process of becoming dilapidated	the organic phenomenon of rotting
a state of deterioration due to old age or long use	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

dilapidation (verb)	decay (verb)
	fall into decay or ruin
	lose a stored charge, magnetic flux, or current
	undergo decay or decomposition