adjective:moving or capable of moving at high speed
The cheetah is a very fast animal.
adjective:fixed securely in place; not moving
The rope was tied fast so it wouldn't slip.
verb:to abstain from all food or drink for a period of time as a religious activity
Many people fast during the holy month of Ramadan.
verb:to attach firmly or secure something
The carpenter fastened the boards together with strong nails.
