show-off vs egotist

show-off and egotist both are nouns.

Word	Noun	Adjective	Verb	Adverb
show-off	Yes	No	No	No
egotist	Yes	No	No	No

As nouns, egotist is a hypernym of show-off; that is, egotist is a word with a broader meaning than show-off:

show-off: someone who deliberately behaves in such a way as to attract attention
egotist: a conceited and self-centered person

Other hypernyms of show-off include egoist, swellhead.

show-off (noun)	egotist (noun)
someone who deliberately behaves in such a way as to attract attention	a conceited and self-centered person