Definition of cool cat in the Idioms Dictionary. cool cat phrase. Finally, Farlex brings you all the rules of English grammar, all in one place, explained in simple. i read somewhere that some person is a cool cat. Best Answer: In the Roaring 20s, the phrase " cool cat " meant This Site Might Help You. A Cool Cat in Town (music by TAPE FIVE) . A cool Antoine Daniel in town . did you sample something for.