expletive vs vocalization

expletive and vocalization both are nouns.

Word	Noun	Adjective	Verb	Adverb
expletive	Yes	No	No	No
vocalization	Yes	No	No	No

As nouns, vocalization is a hypernym of expletive; that is, vocalization is a word with a broader meaning than expletive:

expletive: a word or phrase conveying no independent meaning but added to fill out a sentence or metrical line
vocalization: the use of uttered sounds for auditory communication

Other hypernyms of expletive include utterance.

expletive (noun)	vocalization (noun)
profane or obscene expression usually of surprise or anger	the sound made by the vibration of vocal folds modified by the resonance of the vocal tract
a word or phrase conveying no independent meaning but added to fill out a sentence or metrical line	the use of uttered sounds for auditory communication