小心
to be careful
xiǎoxīn
What does 小心 mean?
小心 (xiǎoxīn) means 'to be careful / watch out / take care.' Literally 'small heart' — the idea is that a 'small (attentive) heart' is a cautious one. Used in three main ways. First, as a standalone warning or command: 小心！ = 'Careful!' / 'Watch out!'
Second, before an object as 'watch out for X': 小心车 = 'watch out for cars'; 小心地滑 = 'caution, slippery floor' (a classic public sign). Third, as an adjective meaning 'careful / cautious': 他做事很小心 = 'he does things carefully.' Two English contrasts: 小心 is closer to 'careful' than 'careful with' — when followed by an object it implies wariness or danger, not gentle handling. For 'be careful with the glass (it's fragile),' you might say 小心点儿 or 轻一点儿 (gentler). The opposite — 'careless' — is 不小心 (bù xiǎoxīn), used adverbially: 我不小心打破了杯子 = 'I accidentally broke the cup.'
Character breakdown
small
heart
Memory hook: 小 (small) + 心 (heart) — keep a 'small, attentive heart' = be careful.
Example sentences
小心！前面有车。
Xiǎoxīn! Qiánmiàn yǒu chē.
Careful! There's a car ahead.
spoken
下雨天，开车要小心。
Xià yǔ tiān, kāi chē yào xiǎoxīn.
On rainy days, drive carefully.
neutral
我不小心把杯子打破了。
Wǒ bù xiǎoxīn bǎ bēizi dǎ pò le.
I accidentally broke the cup.
spoken
请小心地滑。
Qǐng xiǎoxīn dì huá.
Caution: floor is slippery.
written
他做事一直很小心。
Tā zuò shì yìzhí hěn xiǎoxīn.
He's always careful in what he does.
neutral
Common phrases with 小心
Synonyms
注意 means 'pay attention to / notice.' 小心 implies caution about danger; 注意 is broader 'be aware of / take note of.' 注意安全 = 'pay attention to safety'; 小心点儿 = 'be careful.' Public signs often use both: 注意安全，小心地滑.
当心 also means 'watch out / be careful,' very close to 小心 but slightly more formal and warning-oriented — common on warning signs (当心触电 = 'beware of electric shock'). In speech, 小心 is more frequent.