dull, stupid, doltish
懜 centers on a slow, dim mental state: being dull, stupid, or doltish. It describes a lack of sharpness or clarity in thought.
懜 combines the heart radical 忄 with 夢, which likely contributes both sound and the idea of a dream-like, unclear mental state. The exact historical development is uncertain.
The heart radical 忄 beside 夢 (dream) suggests a mind lost in a foggy dream, unable to think sharply. A dull, doltish state like being half-asleep.
For ボウ, imagine a dull student staring blankly at a bow (as in bow and arrow) during class, too doltish to understand its use: bow -> ボウ.