The Indus Dictionary Project
In this ideograph, the symbol for a broken road has been modified by the addition of the symbol for full width. Hence, it translates as 'road missing'.
Mohenjo-daro: Seal: M-391 a: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 96: Collections in India: Suomalainen Tiedeakatemia.
This is Mahadevan's sign number 145, which I have redrawn to better reflect the original.
There is only one extant example of this sign in the corpus of Indus inscriptions.
Road Missing: Lynn Fawcett, 2019.