Alternative form of fastgrowing

(Christianity) A Sunday set aside by the Church of Jesus Christ of Latter-day Saints for fasting by its members, and on which a testimony meeting is held by local congregations.

(obsolete) The treatment of venereal disease by sweating in a hot tub.

Moderately fast; often used to describe a train service which doesn't stop at every station.

Alternative form of colorfast

(idiomatic) Rapid and energetic.

Moving or changing rapidly.

(historical) A con game played with a chain, belt or string that is laid down to form two open loops. The mark places a finger or stick in one of the loops to try and secure (fast) the chain when it gets lifted, but either loop can fast or fail to fast (loose) the chain around the mark's finger/stick depending on where the con artist decides to lift the chain.

Catch! (when throwing an object unexpectedly)

(idiomatic) hold firm