fast¹ / fast/ • adj. 1. moving or capable of moving at high speed. ∎  performed or taking place at high speed; taking only a short time: the journey was fast and enjoyable. ∎  allowing people or things to move at high speed: a wide, fast road. ∎  performing or able to perform a particular type of action quickly: a fast reader. ∎  Sports (of a playing field) likely to make the ball bounce or run quickly or to allow competitors to reach a high speed. ∎  (of a person or lifestyle) engaging in or involving exciting or shocking activities: the fast life she led in London. 2. (of a clock or watch) showing a time ahead of the correct time: I keep my watch fifteen minutes fast. 3. firmly fixed or attached: he made a rope fast to each corner. ∎  (of friends) close and loyal. ∎  (of a dye) not fading in light or when washed. 4. Photog. (of a film) needing only a short exposure.• adv. 1. at high speed: he was driving too fast. ∎  within a short time: they think they're going to get rich fast. 2. so as to be hard to move; firmly or securely: the ship was held fast by the anchor chain. ∎  (of someone or something sleeping) so as to be hard to wake: they were too fast asleep to reply.PHRASES: pull a fast one inf. try to gain an unfair advantage: Joey pulled a fast one on us.fast² • v. [intr.] abstain from all or some kinds of food or drink, esp. as a religious observance.• n. an act or period of fasting: a five-day fast.