crepitate vs rattle

crepitate is not a noun while rattle is a noun.

Word	Noun	Adjective	Verb	Adverb
crepitate	No	No	Yes	No
rattle	Yes	No	Yes	No

As verbs, rattle is a hypernym of crepitate; that is, rattle is a word with a broader meaning than crepitate:

crepitate (noun)	rattle (noun)
	loosely connected horny sections at the end of a rattlesnake's tail
	a baby's toy that makes percussive noises when shaken
	a rapid series of short loud sounds (as might be heard with a stethoscope in some types of respiratory disorders)

crepitate (verb)	rattle (verb)
make a crackling sound	shake and cause to make a rattling noise
	make short successive sounds