fast

Concise Oxford English Dictionary © 2008 Oxford University Press:
fast1

▶adjective

• 1 moving or capable of moving at high speed.

  ■ taking place or acting rapidly.

• 2 (of a clock or watch) showing a time ahead of the correct time.

• 3 firmly fixed or attached.

  ■ (of friends) close and loyal.

  ■ (of a dye) not fading in light or when washed.

• 4 Photography needing only a short exposure.

• 5 involving or engaging in exciting or shocking activities.

▶adverb

• 1 at high speed.

  ■ within a short time.

• 2 so as to be firmly fixed.

• 3 so as to be hard to wake: fast asleep.

– phrases
pull a fast one informal try to gain an unfair advantage.

– origin OE fæst ‘firmly fixed, steadfast’ and fæste ‘firmly, securely’, of Gmc origin.

Concise Oxford English Dictionary © 2008 Oxford University Press:
fast2

▶verb abstain from food or drink. ▶noun an act or period of fasting.

– origin OE fæstan (v.), of Gmc origin.