Someone who, when they prove inconvenient, aggressively rejects social conventions, norms and rules in favor of a less domesticated more feral state.
Anyone who regards any and all traffic instructions such as red lights or stop signs as loose guidelines instead of hard and fast rules should be considered a feralist.
Acting based on instinct, not rational thought. Usually involves things you end up regretting later, that could have been avoided with a little thinking ahead.
Bob likes to get in fights because it makes him feel tough. Bob has already been arrested twice and sued three times because of his fighting, but he continues to fight. Bob is a feralized individual.