小鬼 (xiǎoguǐ): little devil

Meanings

Zhège xiǎoguǐ yòu zài dǎodàn le.

This little rascal is making trouble again.

Xiǎoguǐ, kuài qù xiě zuòyè!

Hey kid, go do your homework!

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小鬼 is informal and can be affectionate (like calling a child "you little rascal") or mildly derogatory depending on tone and context.

小 xiǎo

鬼 guǐ