to long for, dissatisfied, to criticize
觖 centers on a sense of lack or discontent: longing for something absent, feeling dissatisfied, or criticizing what is missing or wrong.
觖 combines 角 (horn) with 夬, which may contribute a phonetic role. The exact historical development is uncertain, and the link between the components and the meanings of longing or dissatisfaction is not clearly established.
Imagine a horn (角) that is missing a piece (夬 suggests a break or gap), leaving you longing for what is absent and dissatisfied enough to criticize the flaw.
For ケツ, picture a dissatisfied critic holding a horn and shouting 'Kets!' in frustration: Kets -> ケツ, capturing the sharp, abrupt sound of complaint.