adj. warm·er, warm·est. 1. Somewhat hotter than temperate; having or producing a comfortable and agreeable degree of heat; moderately hot: a warm climate. 2. Having the natural heat of living beings: a warm body. 3. Preserving or imparting heat: a warm jacket. 4. Having or causing a sensation of unusually high body heat, as from exercise or hard work; overheated. 5. Marked by enthusiasm; ardent: warm support.