Hostility is unfriendliness or opposition that can range from cold rejection to open aggression. When someone shows hostility toward you, they treat you as an enemy or opponent, going beyond simple disagreement to active antagonism. A student might face hostility from a bully who glares at them in the hallway, or a new kid at school might encounter hostility from a clique that refuses to let them join.

Hostility can be quiet or loud. Sometimes it's obvious, like shouting or threatening behavior. Other times it's subtle: turned backs, crossed arms, icy stares, or voices dripping with contempt. You can sense hostility in someone's tone even when their actual words seem neutral.

When a group shows hostility to outsiders, they treat newcomers with suspicion or meanness instead of openness. Hostility poisons relationships and environments: a classroom filled with hostility makes learning difficult, while a welcoming atmosphere helps everyone thrive.

Hostility differs from simple dislike. You might dislike brussels sprouts without feeling hostile toward them. Hostility involves active opposition or antagonism: it's the difference between preferring not to work with someone and actively working against them.