officialese (n.)

early 14c., "minor ecclesiastical court officer" (mid-13c. as a surname), from Old French oficial "law officer; bishop's representative" (12c.) and directly from Late Latin officialis "attendant to a magistrate, public official," noun use of officialis (adj.) "of or belonging to duty, service, or office" (see official (adj.)). From mid-14c. as "a domestic retainer in a household;" the meaning "person in charge of some public work or duty, one holding a civil appointment" is recorded from 1550s.

word-forming element, from Old French -eis (Modern French -ois, -ais), from Vulgar Latin, from Latin -ensem, -ensis "belonging to" or "originating in."