Yes, fast is a Scrabble word!

Adverb

1. Quickly or rapidly (often used as a combining form)

2. Firmly or closely

Verb

1. Abstain from certain foods, as for religious or medical reasons

2. Abstain from eating

Adjective

1. Acting or moving or capable of acting or moving quickly

2. (used of timepieces) indicating a time ahead of or later than the correct time

3. At a rapid tempo

4. (of surfaces) conducive to rapid speeds

5. Resistant to destruction or fading

6. Unrestrained by convention or morality

7. Hurried and brief

8. Securely fixed in place

9. Unwavering in devotion to friend or vow or cause

10. (of a photographic lens or emulsion) causing a shortening of exposure time

Noun

1. Abstaining from food