projectionist (n.)

late 15c., projeccioun, in alchemy, "transmutation by casting a powder on molten metal," from Old French projeccion and directly from Latin proiectionem (nominative proiectio) "a throwing forward, a stretching out," noun of action from past-participle stem of proicere "stretch out, throw forth" (see project (v.)).

From 1560s in the cartographical sense of "system of continuous correspondence between the points of a spherical surface and those of a plane." From 1590s as "action of projecting." From 1756 as "that which projects or juts out."

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.