poser vs exhibitionist

poser and exhibitionist both are nouns.

Word	Noun	Adjective	Verb	Adverb
poser	Yes	No	No	No
exhibitionist	Yes	No	No	No

As nouns, exhibitionist is a hypernym of poser; that is, exhibitionist is a word with a broader meaning than poser:

poser: a person who habitually pretends to be something he is not
exhibitionist: someone who deliberately behaves in such a way as to attract attention

Other hypernyms of poser include show-off.

poser (noun)	exhibitionist (noun)
a particularly difficult or baffling question or problem	someone who deliberately behaves in such a way as to attract attention
a person who poses for a photographer or painter or sculptor	someone with a compulsive desire to expose the genitals
a person who habitually pretends to be something he is not