1. Remove a brace or braces from
   "The orthodontist unbraced her teeth after two years"
    
2. Remove from tension
   "He unbraced the ropes holding the tent"
    
3. Undo the ties of
   "She unbraced her armour after the battle";
   - untie, unlace

Derived forms: unbraced, unbraces, unbracing

Type of: relax, unbend, undo, weaken