1. to assume or take on (a responsibility, debt, or obligation) jointly with another person or party
Usage: formal; legal/financial context

Examples

• Both partners coassume the financial risk of the venture.
• The bank requires that a cosigner coassume the mortgage with the primary borrower.
• When two companies merge, they coassume each other's liabilities.
• The guarantor coassumes the debt obligation alongside the original debtor.
• Parents may coassume student loans to help their children finance education.