Definitions from Wiktionary ( )

▸ adjective:  (dated) Firmly or securely fixed in place; stable.
▸ adjective:  Firm against attack; fortified by nature or art; impregnable; strong.
▸ adjective:  (of people) Steadfast, with unwavering feeling. (Now mostly in set phrases like fast friend(s).)
▸ adjective:  Moving with great speed, or capable of doing so; swift, rapid.
▸ adjective:  (nuclear physics, of a neutron) Having a kinetic energy between 1 million and 20 million electron volts; often used to describe the energy state of free neutrons at the moment of their release by a nuclear fission or nuclear fusion reaction (i.e., before the neutrons have been slowed down by anything).
▸ adjective:  Of a place, characterised by business, hustle and bustle, etc.
▸ adjective:  Causing unusual rapidity of play or action.
▸ adjective:  (computing, of a piece of hardware) Able to transfer data in a short period of time.
▸ adjective:  Deep or sound (of sleep); fast asleep (of people).
▸ adjective:  (of dyes or colours) Not running or fading when subjected to detrimental conditions such as wetness or intense light; permanent.
▸ adjective:  (obsolete) Tenacious; retentive.
▸ adjective:  (dated) Having an extravagant lifestyle or immoral habits.
▸ adjective:  Ahead of the correct time or schedule.
▸ adjective:  (of photographic film) More sensitive to light than average.
▸ adverb:  In a firm or secure manner, securely; in such a way as not to be moved; safe, sound .
▸ adverb:  (of sleeping) Deeply or soundly .
▸ adverb:  Immediately following in place or time; close, very near .
▸ adverb:  Quickly, with great speed; within a short time .
▸ adverb:  Ahead of the correct time or schedule.
▸ noun:  (British, rail transport) A train that calls at only some stations it passes between its origin and destination, typically just the principal stations
▸ verb:  (intransitive) To practice religious abstinence, especially from food.
▸ verb:  (intransitive) To reduce or limit one's nutrition intake for medical or health reasons, to diet.
▸ verb:  (transitive) (academic) To cause a person or animal to abstain, especially from eating.
▸ noun:  The act or practice of fasting, religious abstinence from food
▸ noun:  One of the fasting periods in the liturgical year
▸ noun:  A surname.
▸ noun:  Initialism of Focused assessment with sonography for trauma.
▸ noun:  Abbreviation of Five-hundred-meter Aperture Spherical radio Telescope in China.

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