Probably the same as buwts; mud (as whitish clay) -- mire.
see HEBREW buwts
Jeremiah 38:22HEB:שְׁלֹמֶ֔ךָ הָטְבְּע֥וּ בַבֹּ֛ץ רַגְלֶ֖ךָ נָסֹ֥גוּNAS: were sunk in the mire, They turnedKJV: are sunk in the mire, [and] they are turned awayINT: your close were sunk the mire your feet turned