开心

開心

kāixīn

adjective HSK 2 #545

Meanings

Literally open heart — when your heart opens up, you feel happy.

Jīntiān wǒ hěn kāixīn.

I'm very happy today.

Hé péngyǒu zài yìqǐ hěn kāixīn.

Being with friends makes me happy.

Zhù nǐ shēngrì kuàilè, tiāntiān kāixīn!

Happy birthday, may you be happy every day!

usage

开心 is casual and common in daily speech. 快乐 is slightly more formal and often used in set phrases like 生日快乐.

memory

Think of it as opening your heart — when your heart opens, joy flows in.

开 kāi

心 xīn