clearness of mind, doubtful, uncertain
愰 centers on a mental state that is not fully settled: a mind that is clear in some ways but still doubtful or uncertain. The given meanings describe a mind that is bright yet not entirely free of hesitation.
愰 combines the heart radical 忄 with 晃, which likely contributes both sound and the idea of brightness. The exact historical development is uncertain, but the character probably expresses a bright or clear state of mind.
The heart radical 忄 beside 晃 (bright, shining) suggests a mind that is illuminated but still flickering. Picture a heart that sees clearly yet cannot fully decide, leaving it doubtful.
For オウ, imagine an owl sitting on a branch, its wide eyes showing a clear but uncertain gaze: owl -> オウ, and the owl's mind is bright yet hesitant.