exhibitionist n.

early 14c., "action of displaying," from Old French exhibicion, exibicion "show, exhibition, display," from Late Latin exhibitionem (nominative exhibitio), noun of action from past-participle stem of Latin exhibere "to show, display, present," literally "hold out, hold forth," from ex "out" (see ex-) + habere "to hold" (from PIE root *ghabh- "to give or receive"). Also from early 15c. as "sustenance, food, source of support." Meaning "that which is exhibited" is from 1786.

word-forming element meaning "one who does or makes," also used to indicate adherence to a certain doctrine or custom, from French -iste and directly from Latin -ista (source also of Spanish, Portuguese, Italian -ista), from Greek agent-noun ending -istes, which is from -is-, ending of the stem of verbs in -izein, + agential suffix -tes.

Variant -ister (as in chorister, barrister) is from Old French -istre, on false analogy of ministre. Variant -ista is from Spanish, popularized in American English 1970s by names of Latin-American revolutionary movements.