From Longman Dictionary of Contemporary Englishmouthmouth1 /maʊθ/ ●●● S2 W1 noun (plural mouths /maʊðz/) [countable] 1 faceHB the part of your face which you put food into, or which you use for speaking He lifted his glass to his mouth. Liam was fast asleep with his mouth wide open.2 → keep your mouth shut3 → open your mouth4 → (you) watch your mouth5 entranceDNHOLE the entrance to a large hole or cave As the train entered the mouth of the tunnel, the lights came on.6 riverDNSG the part of a river where it joins the sea the mouth of the River Tees7 bottle/containerDFDH the open part at the top of a bottle or container8 → big mouth9 → me and my big mouth/you and your big mouth etc10 → mouth to feed/hungry mouth11 → make your mouth water12 → down in the mouth13 → out of the mouths of babes (and sucklings)14 → be all mouth → be born with a silver spoon in your mouth at born1(8), → by word of mouth at word1(14), → be foaming at the mouth at foam2(2), → put your foot in your mouth at foot1(15), → put your money where your mouth is at money(18), → put words into somebody’s mouth at word1(22), → shut your mouth at shut1(2), → shoot your mouth off at shoot1(12), → foul-mouthed, mealy-mouthedCOLLOCATIONSverbsopen/shut/close your mouthHe opened his mouth wide so the doctor could examine his throat. cover your mouthShe laughed, covering her mouth with her hand.wipe your mouthHe laid down his fork and wiped his mouth.purse your mouth (=bring your lips tightly together, especially to show disapproval or worry)Ian looked at her and pursed his mouth.kiss somebody on the mouthShe walked boldly up to him and kissed him on the mouth.somebody’s mouth falls/drops open (=in surprise)‘Me?’ she said, her mouth dropping open.somebody’s mouth tightens written (=their lips are pressed tightly together, usually in anger)‘You mean you knew about this?’ His mouth tightened.somebody’s mouth twists written (=moves into an unhappy or angry expression)His mouth twisted in a sneer.adjectivesdry (=especially because someone is nervous or ill)My mouth was dry and my hands were shaking.a big/large/wide/small mouthHe had a big nose and a big mouth.Billy’s wide mouth stretched into a grin.a generous mouth (=a large mouth that is attractive)On her generous mouth was a smile.a full mouth (=with large attractive lips)She had heavy-lidded eyes and a full mouth.a thin mouth (=with thin lips)a woman with a sharp nose and a thin moutha rosebud mouth (=a small red attractive mouth)The girl had huge brown eyes and a rosebud mouth.phrasesthe corner/side of your mouthA smile lifted the corners of her mouth.the roof of your mouth (=the top inside part)He made a clicking sound with his tongue on the roof of his mouth.with your mouth full (=with food in your mouth)Don’t talk with your mouth full.with your mouth openHe chews with his mouth open.(with your) mouth agape written (=with your mouth open in surprise)She stared at him, mouth agape.
Examples from the Corpusmouth• A grimace distorted her fine mouth.• A smile tugged at his mouth.• The hair was already thinning and perhaps to compensate he had grown a luxuriant Groucho moustache which almost hid his mouth.• His mouth gaped and his hands flapped.• He kissed me full on the mouth, one hand at my back, the other straying to my behind.• Babies put everything into their mouths.• The brittle wafer dissolving against the roofs of their mouths was their promise of life in a world beyond Holy Hill.• Try to choose one small enough to go into your mouth whole.