confused, troubled, muddle-headed
憒 centers on a state of mental confusion and inner turmoil: being muddle-headed, troubled, or unable to think clearly.
憒 combines the heart radical 忄 with 貴, which likely contributes the sound and suggests a mind weighed down or disordered, leading to confusion.
The heart 忄 beside 貴 (precious, valuable) suggests a mind so full of precious worries that it becomes muddled and troubled.
For カイ, imagine a confused person trying to find the right key (カイ) to unlock their tangled thoughts: key -> カイ, and the heart is in turmoil.