noun
hairy caterpillar; woolly bear
Refers to caterpillars with conspicuous hair or bristles, often considered unpleasant or irritating to touch.
庭の木に毛虫がたくさんついている。
There are many hairy caterpillars on the tree in the garden.
毛虫に触るとかぶれることがある。
Touching a hairy caterpillar can sometimes cause a rash.
noun
pest; nuisance person
Figurative, colloquial use for an annoying or troublesome person, similar to calling someone a 'pest' or 'nuisance' in English. Not a common modern insult; somewhat dated or playful.
あいつは本当に毛虫みたいなやつだ。
That guy is a real pest.
Compound of 毛 (ke, 'hair') + 虫 (mushi, 'insect, bug'). The reading けむし is a straightforward combination of the kun'yomi readings.