快 (kuài): fast

Meanings

1 fast
2 quick
3 soon
4 happy

Characters

快

kuài

fast; quick; happy

忄 (heart) + 夬 (decisive) - a decisive heart acts quickly.

Examples

HSK 1

快来！

Kuài lái!

Come quickly!

HSK 2

你走得太快了。

Nǐ zǒu de tài kuài le.

You're walking too fast.

HSK 3

电影快要开始了。

Diànyǐng kuàiyào kāishǐ le.

The movie is about to start.

Tips

grammar

快要...了 means 'about to': 快要下雨了 (It's about to rain). This is a very useful pattern.

usage

The 'happy' meaning survives in 快乐 (happy/joyful), as in 生日快乐 (Happy Birthday).

Components

radical

忄 xīn

heart; mind (left-side form)

Vertical heart radical on the left - the side-form of 心. It supplies 快's original meaning, which was 'pleased / glad' (still alive in 快乐 and 痛快). The 'fast' sense developed later but the heart radical kept 快 indexed with mental-state characters such as 忙, 怕, 惯, 性 - all matters of the heart.

phonetic

夬 guài

decisive; resolute

Right component supplies the sound: 夬 → kuài with a velar onset shift. It also adds a faint colour of decisiveness - a heart that acts without hesitation, fitting both 'glad' and 'quick.' The same phonetic appears in 决 (decide), 缺 (lack), 诀 (knack).