to pull out hair, etc., (kokuji)
毮 centers on the action of pulling out hair or similar fine strands, as in plucking or tearing away.
毮 is a kokuji (Japanese-made kanji) combining 扌 (hand) with 毟, a component associated with plucking or pulling hair. The exact historical development is uncertain, but it likely expresses the action of pulling out hair by hand.
The hand radical 扌 on the left reaches toward the right side 毟, which looks like a tuft of hair being pulled. Together they show a hand plucking out hair.
For むし, imagine a hand pulling out hair and a tiny insect (虫, むし) clinging to the strands: むし -> むし, and the hand plucks the hair with the insect still on it.
—