vroom vs howl

vroom and howl both are nouns.

Word	Noun	Adjective	Verb	Adverb
vroom	Yes	No	Yes	No
howl	Yes	No	Yes	No

As verbs, howl is a hypernym of vroom; that is, howl is a word with a broader meaning than vroom:

Other hypernyms of vroom include roar.

vroom (noun)	howl (noun)
the roaring sound made by a motor that is running at high speed	a long loud emotional utterance
	a loud sustained noise resembling the cry of a hound
	the long plaintive cry of a hound or a wolf

vroom (verb)	howl (verb)
make a loud, roaring sound, as of a car engine, while moving	laugh unrestrainedly and heartily
	make a loud noise, as of wind, water, or vehicles
	emit long loud cries
	cry loudly, as of animals