Entry 2 senses Webster, 1913 high-speed · IPA /hˈaɪspˌiːd/ 01 adj. same as fast; as, fast film. Opposite of slow. 1. same as fast; as, fast film. Opposite of slow. See: fast 2. performed at a high rate of speed; as, a high-speed auto chase on the freeway. Syn. hot.