immunosuppressivePronunciation: /ˌɪmjʊnəʊsəˈprɛsɪv, ɪˌmjuːnəʊ-/Definition of immunosuppressive adjective Medicine (chiefly of drugs) partially or completely suppressing the immune response of an individual. noun an immunosuppressive drug. immunosuppressive in other Oxford dictionaries Definition of immunosuppressive in the US English dictionary