Key Difference: Quick is anything which specifies movement. The term, Fast is usually used to specify rate.

Quick and fast are often used interchangeably. They both create confusion because both are used for similar things. There is a difference between both the terms, however they are used as synonyms too.

According to the Dictionary.com, ‘Quick’ is:

• Done, proceeding, or occurring with promptness or rapidity, as an action, process, etc.; prompt; immediate: a quick response.
• That is over or completed within a short interval of time: a quick shower.
• Moving, or able to move, with speed: a quick fox; a quick train.
• Swift or rapid, as motion: a quick flick of the wrist.
• Easily provoked or excited; hasty: a quick temper.

Quick is anything which specifies movement. Synonyms of quick are: rapid, speedy, swift, sudden, fast, etc. Occurring in a short time; happening or doing anything rapidly.

According to the Dictionary.com, ‘Fast’ is:

• Moving or able to move, operate, function, or take effect quickly; quick; swift; rapid: a fast horse; a fast pain reliever; a fast thinker.
• Done in comparatively little time; taking a comparatively short time: a fast race; fast work.
• Indicating a time in advance of the correct time, as of a clock.
• Noting or according to daylight-saving time.
• Adapted to, allowing, productive of, or imparting rapid movement: a hull with fast lines; one of the fastest pitchers in baseball.
• Characterized by unrestrained conduct or lack of moral conventions, especially in sexual relations; wanton; loose: some young people in that era were considered fast, if not downright promiscuous.

The term, fast is usually used to specify rate. Synonyms of fast are: express, hasty, high-speed, prompt, rapid, quick, etc.

Comparison between Quick and Fast:

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