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.

fast1 firm OE.; rapid (after the adv.) XVI; dissipated XVIII. OE. fæst = OS. fast (Du. vast), OHG. festi (G. fest), ON, fastr; prob. orig. :- Gmc. *fastuz (but transf. to other declensions in some langs.).
So adv. firmly OE.; closely; quickly; rapidly XIII; dissipatedly XVII. OE. fæste = OS. fasto (Du. vast), OHG. fasto (G. fast almost), ON. fast :- Gmc. *fastō.

fast2 abstain from food. OE. fæstan = (M)Du. vasten, OHG. fastēn (G. fasten), ON. fasta, Goth. fastan :- Gmc. *fastējan, f. *fastuz; see prec. The gen. sense was ‘hold fast’, hence ‘keep, observe’ (as in Gothic), of which ‘observe abstinence’ was a spec. application.
So sb. act or season of fasting. XII. — ON. fasta = OS., OHG. fasta.

FAST (fɑːst) factor analysis system
• fast automatic shuttle transfer
• Federation Against Software Theft
• first atomic ship transport
• forecasting and assessment in science and technology (in the EU)

FAST Acronym for Federation Against Software Theft. A body set up by the UK software industry to promote the effective and legal use of software, and to take action against those who breach copyright law by making unlicensed copies of proprietary software.