late 15c., "perfect as a result of training," past participle adjective from accomplish (q.v.). Meaning "completed" is from 1570s.
late 14c., from Old French acompliss-, present participle stem of acomplir "to fulfill, fill up, complete" (12c.), from Vulgar Latin *accomplere, from Latin ad- "to" (see ad-) + complere "fill up" (see complete (adj.)). Related: Accomplished; accomplishing.