This is a pictograph of a bow without an arrow. Hence, it is the adjective unarmed.
Illustrative Text Reference:
Kalibangan: Tablet in bas-relief: K-69 A: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 312: Collections in India: Suomalainen Tiedeakatemia.
Image Credit:
Indus Script Sign Number 304: Sign List of the Indus Script: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.