Simplified form of 歡. Phonosemantic compound. 欠 represents the meaning and 雚 represents the sound. 欠 (yawn) is a pictograph of a person with an open mouth, used here to represent a person joyfully laughing.
Components
又(simplified) — Shorthand for the 雚 component in the traditional character 歡.
欠(iconic) — Depicts a person opening their mouth to laugh.