害虫
hài chóng · HSK 7
pest
🐛 害虫 = 害 harm + 虫 insect = a harmful bug, i.e. a pest
害 means harm or injury and 虫 means insect or bug. Stack them and you get the insect that does harm: a pest. The pronunciation hài chóng even starts with hài, the harm part.
害 — 宀 roof + 丯 (phonetic) + 口 mouth
Originally an ideograph showing harm spoken under a roof, with 宀 (roof/house) on top, a phonetic element 丯 in the middle, and 口 (mouth) below suggesting harmful speech. Over time it shifted from 'injury caused by words' to the broader senses of 'harm,' 'injure,' and 'fear.'