Webster's Revised Unabridged Dictionary · 1913

exhibitionist

exhibitionist , noun

1.
a person with a compulsive desire to expose the genitals; -- usually a male.
2.
someone who deliberately behaves in such a way as to attract attention.

exhibitionist , adjective

1.
compulsively attracting attention to oneself especially by boasting or exaggerated behavior.

Also: exhibitionistic