Right side
欠 — pictograph of a person leaning forward with mouth open, originally 'to exhale, gape, yawn.' The indexing radical, marking
欺 in the family of mouth-expression verbs:
歌 to sing,
欢 joy,
歇 to rest. Semantic logic:
欺 is to deceive by speaking — bending toward someone and pouring out false words.
