rejoice
懽 centers on joyful emotion: to rejoice or be glad. It expresses a heartfelt, celebratory happiness.
懽 combines the heart radical 忄 with the phonetic component 雚, which likely contributes the sound and may carry an associated sense of joy or exuberance.
The heart radical 忄 beside 雚 suggests a heart filled with joy. Picture a heart so happy it feels like it's bursting with celebration.
For カン, imagine a can of happiness: when you open it, joy pours out. Can -> カン, and your heart rejoices.