(fast, fäst) adjective
1. Firm in place; not easily moved.
2. Firmly secured or bound.
3. Constant; steadfast.
4. Unfadable: said of colors.
5. Resistant: acid–fast.
6. Sound or deep, as sleep.
7. Acting or moving quickly; swift.
8. Performed quickly: fast work.
9. Adapted to, or suitable for, quick movement: a fast track.
10. Requiring rapidity of action or motion: a fast schedule.
11. Indicating a time in advance of the true time: The clock is fast.
12. Given to dissipation or moral laxity: fast living.
13. Phot. Intended for short exposure, as a high–velocity shutter or a highly sensitive film.
—adverb
1. Firmly; fixedly; securely.
2. Soundly: fast asleep.
3. Quickly; rapidly; swiftly.
4. In quick succession: His thoughts came fast
5. Dissipatedly; recklessly: to live fast.
6. Archaic Near: fast by.
—noun
1. Something which is firm or fixed, as shore ice.
2. A mooring line. [OE fœst]

(fast, fäst) v.i.
1. To abstain from food.
2. To go without food, wholly or in part, as in observance of a religious duty.
—noun
1. Abstinence from food, partial or total, or from prescribed kinds of food, particularly as a religious duty.
2. A period prescribed for religious fasting and other observances: opposed to feast. [OE fœstan]