[ noun mouth; verb mouth ]
See synonyms for: mouthmouthedmouthing on

noun,plural mouths [mouthz]. /maʊðz/.
  1. Anatomy, Zoology.

    • the opening through which an animal or human takes in food.

    • the cavity containing the structures used in mastication.

    • the structures enclosing or being within this cavity, considered as a whole.

  2. the masticating and tasting apparatus.

  1. a person or animal dependent on someone for sustenance: another mouth to feed.

  2. the oral opening or cavity considered as the source of vocal utterance.

  3. utterance or expression: to give mouth to one's thoughts.

  4. talk, especially loud, empty, or boastful talk: That man is all mouth.

  5. disrespectful talk or language; back talk; impudence.

  6. a grimace made with the lips.

  7. an opening leading out of or into any cavity or hollow place or thing: the mouth of a cave; a bottle's mouth.

  8. the outfall at the lower end of a river or stream, where flowing water is discharged, as into a lake, sea, or ocean: the mouth of the Nile.

  9. the opening between the jaws of a vise or the like.

  10. the lateral hole of an organ pipe.

  11. the lateral blowhole of a flute.

verb (used with object)
  1. to utter in a sonorous or pompous manner, or with excessive mouth movements: to mouth a speech.

  2. to form (a word, sound, etc.) with the lips without actually making an utterance: She silently mouthed her answer so as not to wake her napping child.

  1. to utter or pronounce softly and indistinctly; mumble: Stop mouthing your words and speak up.

  2. to put or take into the mouth, as food.

  3. to press, rub, or chew at with the mouth or lips: The dog mouthed the toys.

  4. to accustom (a horse) to the use of the bit and bridle.

verb (used without object)
  1. to speak sonorously and oratorically, or with excessive mouth movement.

  2. to grimace with the lips.

Verb Phrases
  1. mouth off, Slang.

    • to talk back; sass: He mouthed off to his mother.

    • to express one's opinions, objections, or the like in a forceful or uninhibited manner, especially in public.

Idioms about mouth

  1. down in / at the mouth, Informal. dejected; depressed; disheartened: Ever since he lost his job, he has been looking very down in the mouth.

  2. run off at the mouth, Informal. to talk incessantly or indiscreetly.

  1. talk out of both sides of one's mouth, to make contradictory or untruthful statements.

Origin of mouth

before 900; Middle English; Old English mūth; cognate with German Mund,Old Norse munnr

Other words for mouth

Other words from mouth

  • mouther, noun
  • mouthless, adjective
  • outmouth, verb (used with object)

Words Nearby mouth Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use mouth in a sentence

British Dictionary definitions for mouth


noun(maʊθ) plural mouths (maʊðz)
  1. the opening through which many animals take in food and issue vocal sounds

  2. the system of organs surrounding this opening, including the lips, tongue, teeth, etc

  1. the visible part of the lips on the face: Related adjectives: oral, oscular

  2. a person regarded as a consumer of food: four mouths to feed

  3. verbal expression (esp in the phrase give mouth to)

  4. a particular manner of speaking: a foul mouth

  5. informal boastful, rude, or excessive talk: he is all mouth

  6. the point where a river issues into a sea or lake

  7. the opening of a container, such as a jar

  8. the opening of or place leading into a cave, tunnel, volcano, etc

  9. that part of the inner lip of a horse on which the bit acts, esp when specified as to sensitivity: a hard mouth

  10. music the narrow slit in an organ pipe

  11. the opening between the jaws of a vice or other gripping device

  12. a pout; grimace

  13. by word of mouth orally rather than by written means

  14. down in the mouth or down at the mouth in low spirits

  15. have a big mouth or open one's big mouth informal to speak indiscreetly, loudly, or excessively

  16. keep one's mouth shut to keep a secret

  17. put one's money where one's mouth is to take appropriate action to support what one has said

  18. put words into someone's mouth

    • to represent, often inaccurately, what someone has said

    • to tell someone what to say

  19. run off at the mouth informal to talk incessantly, esp about unimportant matters

  1. to speak or say (something) insincerely, esp in public

  2. (tr) to form (words) with movements of the lips but without speaking

  1. (tr) to accustom (a horse) to wearing a bit

  2. (tr) to take (something) into the mouth or to move (something) around inside the mouth

  3. (intr usually foll by at) to make a grimace

Origin of mouth

Old English mūth; compare Old Norse muthr, Gothic munths, Dutch mond

Derived forms of mouth

  • mouther (ˈmaʊðə), noun

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Idioms and Phrases with mouth


In addition to the idiom beginning with mouth

  • mouth off

also see:

  • bad mouth
  • big mouth
  • butter wouldn't melt in one's mouth
  • down in the dumps (mouth)
  • foam at the mouth
  • foot in one's mouth
  • from the horse's mouth
  • hand to mouth
  • have one's heart in one's mouth
  • keep one's mouth shut
  • laugh out of the other side of one's mouth
  • leave a bad taste in one's mouth
  • look a gift horse in the mouth
  • make one's mouth water
  • melt in one's mouth
  • not open one's mouth
  • out of the mouths of babes
  • put one's money where one's mouth is
  • put words in someone's mouth
  • run off at the mouth
  • shoot off one's mouth
  • take the bit in one's mouth
  • take the bread out of someone's mouth
  • take the words out of someone's mouth
  • word of mouth

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.