Usage note
“咳”是一个短促的声音，常用来引起注意或表示轻微咳嗽。
hāi shì yī gè duǎn cù de shēng zǐ ， cháng lái yòng lái yǐng xíng zhù zhi huò bǎo shí mián qīng ké.
"咳" is a short sound often used to get someone's attention or to indicate a slight cough.
Context note
“咳”常用于日常生活中，比如在别人说话时打断对方或是在轻微咳嗽后。
hāi cháng yòng yú rì chén shēn qíng zhōng ， bǐ rú zài bié rén shuō huà shí duàn dào fǎng fā huò shì zài mián qiān kěng hòu 。
"咳" is commonly used in daily life, such as when interrupting someone while they are speaking or after a slight cough.
5 examples
他在说话时突然咳嗽了一下，我听到后轻咳了一声。
tā zài shuō huà shí tū rán ké sou le yí xià， wǒ tīng dào hòu qīng hāi le yì shēng。
He suddenly coughed while talking, and I responded with a light cough.
当有人打断你讲话时，你可以用“咳”来表示不满。
dāng yǒu rén dǎ duàn nǐ jiǎng huà shí， nǐ kě yǐ yòng “ hāi ” lái biǎo shì bù mǎn。
When someone interrupts you while speaking, you can use "咳" to show your dissatisfaction.
他咳嗽了几声后，感觉舒服多了。
tā ké sou le jǐ shēng hòu， gǎn jué shū fú duō le。
After coughing a few times, he felt much better.
听到他的声音，我轻咳了一声回应。
tīng dào tā de shēng yīn， wǒ qīng hāi le yì shēng huí yìng。
I responded with a light cough when I heard his voice.
他咳嗽了一下，然后继续讲话。
tā ké sou le yí xià， rán hòu jì xù jiǎng huà。
He coughed once and then continued speaking.
5 mini stories
妈妈在厨房做饭时突然轻咳了一声，爸爸听到后问她怎么了。
mā mā zài chú fáng zuò fàn shí tū rán qīng hāi le yì shēng， bà ba tīng dào hòu wèn tā zěn me le。
Mom suddenly gave a light cough while cooking in the kitchen, and Dad asked her what was wrong after hearing it.
小明在课堂上突然咳嗽了几声，老师让他站起来回答问题。
xiǎo míng zài kè táng shàng tū rán ké sou le jǐ shēng， lǎo shī ràng tā zhàn qǐ lái huí dá wèn tí。
Xiaoming suddenly coughed several times in class, and the teacher made him stand up to answer a question.
朋友之间聊天时，如果一方轻咳一声，另一方可能会意识到自己说错了话。
péng yǒu zhī jiān liáo tiān shí， rú guǒ yì fāng qīng hāi yì shēng， lìng yì fāng kě néng huì yì shí dào zì jǐ shuō cuò le huà。
When friends are chatting, if one person gives a light cough, the other might realize they said something wrong.
在公共场合，人们会用“咳”来提醒别人注意自己的咳嗽声。
zài gōng gòng chǎng hé， rén men huì yòng “ hāi ” lái tí xǐng bié rén zhù yì zì jǐ de ké sou shēng。
In public places, people use "咳" to remind others of their own coughing sound.
医生建议病人如果轻微咳嗽可以轻咳一声表示自己还好。
yī shēng jiàn yì bìng rén rú guǒ qīng wēi ké sou kě yǐ qīng hāi yì shēng biǎo shì zì jǐ hái hǎo。
The doctor advised patients who have a slight cough to give a light cough to indicate they are okay.
Mini dialogue
打招呼
A
咳，你好！
Hāi, nǐ hǎo!
Hey, hello!
B
咳，好久不见！
Hāi, hǎo jiǔ bù jiàn!
Hey, long time no see!
引起注意
A
咳，你的书掉了。
Hāi, nǐ de shū diào le.
Hey, you dropped your book.
B
咳，谢谢你！
Hāi, xièxie nǐ!
Hey, thank you!
Related words and contrasts
similar
喂
wèi
hello (on phone), hey
Both are used to get attention. 咳 is a softer 'hey', while 喂 is common when answering a phone.
similar
嗨
hāi
hi, hey
嗨 is a friendly greeting borrowed from English 'hi'. 咳 is more like calling out 'hey!' to someone.