1. a singer who produces a tune without opening the lips or forming words • Derivationally related forms: hum • Hypernyms: singer, vocalist, vocalizer, vocaliser 2.(baseball) a pitch thrown with maximum velocity - he swung late on the fastball - he showed batters nothing but smoke • Syn: fastball, heater, smoke, bullet • Topics: baseball, baseball game • Hypernyms: pitch, delivery • Hyponyms: slider