antipsychotic Syllabification: (an·ti·psy·chot·ic)Pronunciation: /ˌantēsīˈkätik, ˌantī-/Definition of antipsychotic adjective [attributive] (chiefly of a drug) used to treat psychotic disorders. noun an antipsychotic drug. antipsychotic in other Oxford dictionaries Definition of antipsychotic in the British & World English dictionary