From Longman Dictionary of Contemporary Englishchinchin /tʃɪn/ ●●● W3 noun [countable] 1 HBHthe front part of your face below your mouth He rubbed his chin thoughtfully.2 → (keep your) chin up!3 → take something on the chinCOLLOCATIONSadjectivesa double chin (=loose skin under your chin that looks like a second chin)Frank was much fatter now and he had a double chin.a pointed chinShe had a narrow face and a pointed chin.a weak chin (=small in proportion to the face, and not square in shape)He’s grown a beard to cover his weak chin.a determined chin literary (=giving a face a determined appearance)She had short hair and a determined chin.a square chinA square chin may be taken as a sign of a stubborn character.a receding chin (=sloping backwards in an unattractive way)Half the boys in my college seemed to have receding chins.an unshaven chin (=with short hairs on because a man has not shaved)His combed hair looked oddly neat against his unshaven chin.verbsstroke/rub your chin (=stroke it in a way that shows you are thinking about something)He stroked his chin and then seemed to come to a decision.
Examples from the Corpus
chin• Her head was back and her chin raised, resin plugging the eye sockets.• Dolly watched him, bedclothes up to her chin.• Her chin is low and stubborn and insane.• The night before the trials, he shaved a gnarly goatee off his chin.• Lufkin stroked his chin, as if contemplating her request.• He smelled light sweat, felt spittle reaching to his chin.• His chin hung farther down on his chest as his shoulders hunched closer together.• Her short red hair was crudely shaped in a wedge and her pallid cheeks and small chin were peppered with unsightly acne.Origin chin Old English cinn 