嘴硬

嘴硬	zuǐ yìng	reluctant to admit a mistake
嘴	zuǐ	mouth / beak / nozzle / spout (of teapot etc) / CL:张,个
硬	yìng	hard; stiff; solid / (fig.) strong; firm / resolutely; uncompromisingly / laboriously; with great difficulty / good (quality); able (person) / (of food) filling; substantial