A conformist is a person who follows traditional standards of conduct. If you're a conformist, it's unlikely you'll join a revolution to overthrow your government; instead you'll argue that it's best to keep things the way they are.
Conformist comes from the Old French word conformer, which means "to agree to, make or be similar, be agreeable." People sometimes use the term conformist in a negative way, as an insult implying that someone doesn't have the brains or the guts to question the status quo. Conformist can also be used as an adjective to describe something that follows convention and established customs. A conformist school board, for example, would follow the usual time-tested curriculum.