<p><strong>Noun</strong></p><ul><li>a mouth, plural mouths.</li><li>Anatomy, Zoology: the opening through which an animal or human takes in food.</li><li>the cavity containing the structures used in mastication.</li><li>the structures enclosing or being within this cavity, considered as a whole.</li><li>the masticating and tasting apparatus.</li><li>a person or animal dependent on someone for sustenance: another mouth to feed.</li><li>the oral opening or cavity considered as the source of vocal utterance.</li><li>utterance or expression: to give mouth to one's thoughts.</li><li>Synonyms: speech, voice.</li><li>talk, especially loud, empty, or boastful talk: That man is all mouth.</li><li>disrespectful talk or language; back talk; impudence.</li><li>a grimace made with the lips.</li><li>an opening leading out of or into any cavity or hollow place or thing: the mouth of a cave; a bottle's mouth.</li><li>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.</li><li>the opening between the jaws of a vise or the like.</li><li>the lateral hole of an organ pipe.</li><li>the lateral blowhole of a flute.</li></ul><p><strong>Verb</strong></p><ul><li>(used with object) to utter in a sonorous or pompous manner, or with excessive mouth movements: to mouth a speech.</li><li>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.</li><li>to utter or pronounce softly and indistinctly; mumble: Stop mouthing your words and speak up.</li><li>to put or take into the mouth, as food.</li><li>to press, rub, or chew at with the mouth or lips: The dog mouthed the toys.</li><li>to accustom (a horse) to the use of the bit and bridle.</li><li>(used without object) to speak sonorously and oratorically, or with excessive mouth movement.</li><li>to grimace with the lips.</li><li>(verb phrase) Slang: to talk back; sass: He mouthed off to his mother.</li><li>to express one's opinions, objections, or the like in a forceful or uninhibited manner, especially in public.</li></ul>