Definition of FAST

moving, proceeding, or acting with great speed <the fast pace of construction resulted in our new house being done ahead of schedule>
Phrases at speed [chiefly British]
Antonyms slow
firmly positioned in place and difficult to dislodge <the rusty, old screws are so fast in the fitting that there's no hope of getting them out>
Antonyms insecure, loose
given to or marked by cheating and deception <rolling back odometers was just one of the fast practices that the used-car dealer was guilty of>
marked by the ability to withstand stress without structural damage or distortion <as the storm approached, we checked to see that every thing on the outside of the house was fast and locked in position>
having or showing quickness of mind <I don't know how to operate this machine, but I'm a fast learner>

Seen & Heard

What made you want to look up fast[adjective]? Please tell us where you read or heard it (including the quote, if possible).