ノウ, なや.む, なや.ます, なや.ましい, なやみ
trouble, worry, in pain, distress, illness
JLPT2 G7 S10 F1084
The relevant seal inscription form of ?# shows hair curling over a scalp, with the form ?transforming the element into a cranium with three bending lines suggesting wrinkles in the soft brains. 惱 adds 心 heart/emotions → persistent thoughts (compare 願 and 慮) of a disturbing nature running about the brain → *distress*; *trouble*; *affliction*; *worry* → *harass*.
[Full Kanji Etymology List]