Unwilling to interact with other people or engage in social activities; or against the norms and rules of society.
From the prefix 'anti-' (against) combined with 'social' from Latin 'socialis' (of allies or companions). The term emerged in the 1800s as psychology developed frameworks for understanding behavior.
Interestingly, 'antisocial' behavior has two meanings that confuse people: simple shyness (not liking parties) versus genuinely harmful behavior (breaking rules). Psychologists use 'asocial' for withdrawn people and reserve 'antisocial' for people who harm society—but most people use it to mean just being quiet.
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