Timeserver(n.) One who adapts his opinions and manners to the times; one who obsequiously compiles with the ruling power; -- now used only in a bad sense.
Thesaurus Entries
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