The Indus Dictionary Project
This is the pictograph of an adult person, with the addition of a bar across one leg. The bar may depict a wooden legcuff. The leg area can give us information about the status of the person. In this instance, we can see that his movement has been deliberately restricted by the legcuff. Hence, I infer that this is the noun slave.
Mohenjo-daro: Seal: M-380 a: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 94: Collections in India: Suomalainen Tiedeakatemia.
Mohenjo-daro: Seal: M-1281 a: Sayid Ghulam Mustafa Shah and Asko Parpola, 1991: Corpus of Indus Seals and Inscriptions: Volume 2: Page 163: Collections in Pakistan: Suomalainen Tiedeakatemia.
Indus Script Sign Number 2266: List of Sign Variants: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.