subservient (adj.)
1630s, "useful, serviceable," from Latin subservientem (nominative subserviens), present participle of subservire "assist, serve, come to the help of, lend support," from sub "under" (see sub-) + servire "serve" (see serve (v.)). The meaning "slavishly obedient" is first recorded 1794. Related: Subserviently.