Defying one's parents was a grave offense in ancient times.
Tips
usage
Literary/classical character. In modern Chinese it almost always appears in the compound 忤逆 (wǔnì) - to disobey, especially to be unfilial toward one's parents. The 忄 (heart) radical signals the emotional/moral nature of the act.
Heart radical on the left in its compressed three-stroke side-form - the indexing radical. Defiance, contrariness, going against authority are all states of the heart in classical Chinese psychology, so the radical does direct semantic work. Same family of emotion verbs: 怕 (fear), 怒 (anger), 怨 (resent), 恨 (hate), 悔 (regret).
Right side 午 supplies the sound wǔ directly with no drift. 午 originally pictured a pestle pounding downward - a head-on crossing motion that doubles as a faint semantic hint: 忤 means to push back against someone's will, head against head. Same phonetic seeds 许 (permit) and 仵 (pair up).
