the white flowering head of reeds or other grasses appearing in profusion

那是一场如火如荼的革命运动。

verb · a bitter-tasting edible plant, specifically the common sowthistle (Sonchus oleraceus)

谁谓荼苦，其甘如荠。

bitter hardship, misery, or cruelty

残暴的统治使百姓深陷于荼毒之中。