whirr vs emit

whirr is a noun but emit is not a noun.

Word	Noun	Adjective	Verb	Adverb
whirr	Yes	No	Yes	No
emit	No	No	Yes	No

As verbs, emit is a hypernym of whirr; that is, emit is a word with a broader meaning than whirr:

Other hypernyms of whirr include let loose, let out, utter.

whirr (noun)	emit (noun)
sound of something in rapid motion

whirr (verb)	emit (verb)
make a vibrant sound, as of some birds	expel (gases or odors)
make a soft swishing sound	express audibly; utter sounds (not necessarily words)
	give off, send forth, or discharge; as of light, heat, or radiation, vapor, etc.