fast

acting or moving or capable of acting or moving quickly

• “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

• “my watch is fast”

at a rapid tempo

• “the band played a fast fox trot”

(of surfaces) conducive to rapid speeds

• “a fast road”
• “grass courts are faster than clay”

firmly fastened or secured against opening

• “windows and doors were all fast”
• “a locked closet”
• “left the house properly secured”

resistant to destruction or fading

• “fast colors”

unrestrained by convention or morality

• “Congreve draws a debauched aristocratic society”
• “deplorably dissipated and degraded”
• “riotous living”
• “fast women”

hurried and brief

• “paid a flying visit”
• “took a flying glance at the book”
• “a quick inspection”
• “a fast visit”

securely fixed in place

• “the post was still firm after being hit by the car”

unwavering in devotion to friend or vow or cause

• “a firm ally”
• “loyal supporters”
• “the true-hearted soldier...of Tippecanoe” Campaign song for William Henry Harrison
• “fast friends”

quickly or rapidly (often used as a combining form)

• “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 tightly

• “held fast to the rope”
• “her foot was stuck fast”
• “held tight”

abstaining from food

abstain from certain foods, as for religious or medical reasons

• “Catholics sometimes fast during Lent”

abstain from eating

• “Before the medical exam, you must fast”