mediocre UK /ˌmiːdɪˈəʊkə/US /ˌmidiˈoʊkəɹ/noun 2adjective 1forms 3 noun2 •A person of minor significance, accomplishment or acclaim; a common and undistinguished person. •(historical) A member of a socioeconomic class between the upper ranks of society and the agricultural workers. adjective1 •Not excellent or outstanding, usually disappointingly so.I'm pretty good at tennis but only mediocre at racquetball. formsmediocres · more mediocre · most mediocre