What is the meaning of fast?

noun

• Abstaining from food.
  • synonyms: fasting

verb

• Abstain from certain foods, as for religious or medical reasons.
  • usage: "Catholics sometimes fast during Lent"
• Abstain from eating.
  • usage: "Before the medical exam, you must fast"

adjective

• Acting or moving or capable of acting or moving quickly.
  • usage: "fast film"; "on the fast track in school"; "set a fast pace"; "a fast car"
• Used of timepieces. ( indicating a time ahead of or later than the correct time)
  • usage: "my watch is fast"
• At a rapid tempo.
  • usage: "the band played a fast fox trot"
• Of surfaces. ( conducive to rapid speeds)
  • usage: "a fast road"; "grass courts are faster than clay"
• Resistant to destruction or fading.
  • usage: "fast colors"
• Unrestrained by convention or morality.
  • usage: "Congreve draws a debauched aristocratic society"; "deplorably dissipated and degraded"; "riotous living"; "fast women"
  • synonyms: debauched, degenerate, degraded, dissipated, dissolute, libertine, profligate, riotous
• Hurried and brief.
  • usage: "paid a flying visit"; "took a flying glance at the book"; "a quick inspection"; "a fast visit"
  • synonyms: flying, quick
• Securely fixed in place.
  • usage: "the post was still firm after being hit by the car"
  • synonyms: firm, immobile
• Unwavering in devotion to friend or vow or cause.
  • usage: "a firm ally"; "loyal supporters"; "the true-hearted soldier... Of Tippecanoe- Campaign song for William Henry Harrison; "fast friends"
  • synonyms: firm, loyal, truehearted
• Of a photographic lens or emulsion. ( causing a shortening of exposure time)
  • usage: "a fast lens"

adverb

• Quickly or rapidly (often used as a combining form))
  • usage: "how fast can he get here"; "ran as fast as he could"; "needs medical help fast"; "fast-running rivers"; "fast-breaking news"; "fast-opening (or fast-closing. shutters"
• Firmly or closely.
  • usage: "held fast to the rope"; "her foot was stuck fast"; "held tight"
  • synonyms: tight