kǔ shuǐ
bitter water (e.g. mineral water containing sulfates)
suffering
digestive fluids rising from stomach to the mouth
fig. bitter complaint
tǔ kǔ shuǐ
to have bitter digestive fluids rising to the mouth
fig. to complain bitterly
to pour out one's sufferings
dào kǔ shuǐ
to pour out one's grievances