Timeserver :  (noun)

1: one who conforms to current ways and opinions for personal advantage

Benedict Arnold, Brutus, Judas, Judas Iscariot, Quisling, Vicar of Bray, apple-polisher, archtraitor, ass-licker, backscratcher, backslapper, betrayer, bootlick, bootlicker, brown-nose, brownie, careerist, chameleon, clawback, cockatrice, conniver, conspirator, conspirer, courtier, creature, cringer, double agent, double-crosser, double-dealer, dupe, egotist, fawner, flatterer, flunky, footlicker, formalist, fortune hunter, groveler, handshaker, helot, hog, individualist, informer, instrument, intrigant, intriguer, jackal, kowtower, lackey, led captain, lickspit, lickspittle, lone wolf, loner, machinator, mealymouth, minion, monopolist, narcissist, peon, plotter, puppet, quisling, rat, road hog, schemer, self-advancer, self-pleaser, self-seeker, self-server, serf, serpent, slave, snake, spaniel, stooge, suck, sycophant, temporizer, timepleaser, toad, toady, tool, traitor, treasonist, trimmer, truckler, tufthunter, turncoat, weathercock, yes-man,