- 狮子大开口 shīzidàkāikǒu to demand an exorbitant priceto make excessive or unreasonable demands, especially regarding money; daylight robbery
- 开口闭口 kāikǒubìkǒu to talk repeatedlywhenever one opens their mouth; to say the same thing again and again
- 开口子 kāikǒuzi to breach a diketo break through or burst a dike or embankment due to flooding
- 开口跳 kāikǒutiào clown skilled in martial artsA clown role in traditional Chinese opera skilled in both acrobatics and articulate, powerful speech; literally translates as "open-mouth jump".
- 衣来伸手,饭来开口 yīláishēnshǒufànláikāikǒu to lead an idle and pampered lifeto stretch out one's hands when clothes are offered and open one's mouth when food is served; describes being lazy and expecting everything to be done for oneself
- 吃开口饭 chīkāikǒufàn to make a living through speaking or performingTo earn a living using one's voice or speaking skills, such as by performing opera, storytelling, or crosstalk.
- 饭来开口 fànláikāikǒu to lead an easy lifeTo lead an easy life where everything is provided; describes being idle and lazy, waiting to be served. Often used in the phrase [[衣来伸手,饭来开口|衣來伸手,飯來開口|yi1 lai2 shen1 shou3 fan4 lai2 kai1 kou3]].
- 开口呼 kāikǒuhū open-mouth soundIn Chinese phonetics, a syllable that begins with a vowel other than [[衣|衣|yi1]], [[屋|屋|wu1]], or [[迂|迂|yu1]]; it refers to syllables with no medial glide.
- 开口成脏 kāikǒuchéngzāng to use foul language(Internet slang) to speak using profanity or dirty words; this is a pun on the idiom [[出口成章|出口成章|chu1 kou3 cheng2 zhang1]]
- 开口笑 kāikǒuxiào to smile broadlyTo open one's mouth and laugh or smile; used to describe a happy or optimistic mood.