Efficient
late Middle English (in the sense ‘making, causing’, usually in efficient cause): from Latin efficient- ‘accomplishing’, from the verb efficere (see effect). The current sense dates from the late 18th century.
wiktionary
1398, “making,” from Old French, from Latin efficientem, nominative efficiēns, participle of efficere(“work out, accomplish”) (see effect). Meaning “productive, skilled” is from 1787. Efficiency apartment is first recorded 1930, American English. [1]
etymonline
efficient (adj.)
late 14c., "making, producing immediate effect, active, effective," from Old French efficient and directly from Latin efficientem (nominative efficiens) "effective, efficient, producing, active," present participle of efficere "work out, accomplish," from assimilated form of ex "out" (see ex-) + facere "to do" (from PIE root *dhe- "to set, put"). Meaning "productive, skilled" is from 1787. Related: Efficiently.
