‘睡觉’ (shuì jiào) is a common colloquial verb meaning 'to sleep'. It combines two characters: 睡 (shuì), which means 'to sleep' and carries the core action, and 觉 (jiào), which in this compound functions as a nominal suffix indicating the state or act of sleeping — together they form an inseparable, frequently used verb phrase. Unlike the more formal or literary word '睡眠' (shuìmián), ‘睡觉’ is used in everyday speech across all age groups and contexts, from telling children to rest to discussing adult sleep habits.

This verb is typically used in simple declarative sentences, often with time or duration markers (e.g., 了, 一会儿, 八个小时). It does not take the aspect particle ‘着’ (*shuì zhe*) for continuous aspect — instead, ‘在睡觉’ is used for ‘is sleeping’. The word is rarely used as a noun; if you need a noun meaning ‘sleep’, use ‘睡眠’ or ‘觉’ (jiào) alone in informal contexts (e.g., ‘我困了，想睡个觉’ — ‘I’m tired, I want to take a nap’).