assistant
n.
mid-15c., assistent "one who helps or aids another," from Middle French assistent, adjective and noun, properly present participle of assister (see assist, v.).
adj.
mid-15c., "helpful, of assistance," from Middle French assistent (see assistant, n.).
〔李〕[assist v. 帮助；-ant →] n. a person who assists anoth-er；helper助手；帮手