1. removes braces or supports from something
2. relaxes or weakens something that was tense or firm

Examples

• The carpenter unbraces the wooden frame after the glue dries.
• She unbraces her shoulders and takes a deep breath.
• The worker unbraces the scaffolding once construction is complete.
• He unbraces his legs and sits down comfortably.
• The engineer unbraces the temporary supports from the bridge.
• After the performance, the dancer unbraces her posture and relaxes.