trifluoperazinePronunciation: /ˌtrʌɪfluːə(ʊ)ˈpɛrəziːn/Definition of trifluoperazine noun [mass noun] Medicine an antipsychotic and sedative drug related to phenothiazine. Origin: 1950s: from tri- + fluo(rine) + (pi)perazinetrifluoperazine in other Oxford dictionaries Definition of trifluoperazine in the US English dictionary