Hostile
Part of speech: noun
Definition: An enemy; esp., an American Indian in arms against the whites; -- commonly in the plural.
Part of speech: adjective
Definition: Belonging or appropriate to an enemy; showing the disposition of an enemy; showing ill will and malevolence, or a desire to thwart and injure; occupied by an enemy or enemies; inimical; unfriendly
Example sentence: The aim is to create here in Britain a really hostile environment for illegal migration.
Aggressive
Part of speech: adjective
Definition: Tending or disposed to aggress; characterized by aggression; making assaults; unjustly attacking.
Example sentence: I think people who go through a lot, they're aggressive.