noise vs drown out

noise is a noun but drown out is not a noun.

Word	Noun	Adjective	Verb	Adverb
noise	Yes	No	Yes	No
drown out	No	No	Yes	No

As verbs, drown out is a hyponym of noise; that is, drown out is a word with a more specific, narrower meaning than noise:

noise (noun)	drown out (noun)
the quality of lacking any predictable order or plan
incomprehensibility resulting from irrelevant information or meaningless facts or remarks
the auditory experience of sound that lacks musical quality; sound that is a disagreeable auditory experience
a loud outcry of protest or complaint
sound of any kind (especially unintelligible or dissonant sound)
electrical or acoustic activity that can disturb communication

noise (verb)	drown out (verb)
emit a noise	make imperceptible