educationist n.

1530s, "child-rearing," also "the training of animals," from French education (14c.) and directly from Latin educationem (nominative educatio) "a rearing, training," noun of action from past-participle stem of educare (see educate). Originally of instruction in social codes and manners; meaning "systematic schooling and training for work" is from 1610s.

All education is despotism. [William Godwin, "Enquirer," 1797] 

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.