0.02 sec. un·brace ( n-br s ). tr.v. un·braced, un·brac·ing, un·brac·es. 1. To set free by removing bands or braces. 2. To release from tension; relax. 3. To make slack; weaken. unbrace [ʌnˈbreɪs]. vb (tr). 1. to remove tension or strain from; relax ...