IPA: /ˌæn.tiˈsoʊ.ʃəl/
KK: /ˌæntiˈsoʊʃəl/
Not friendly or sociable; showing a lack of interest in interacting with others or behaving in a way that is harmful to social norms.
His antisocial behavior made it difficult for him to make friends.
Antisocial is formed from "anti-" (meaning against) and "socialis" (from Latin, meaning social or pertaining to society). The word describes behavior that is against social norms or interactions.
Think of 'against' ('anti-') and 'society' ('socialis') to remember that 'antisocial' refers to behavior that goes against social interaction.