suān

Frequency star
  1. sour, tart, acidic (taste)
  2. acid (chemistry)
  3. to feel sore, to ache
  4. jealous, envious, sarcastic, bitter, cynical (informal)

這檸檬太酸了,我的臉都皺起來了。

This lemon is so sour that my face is all scrunched up.