Doubly strengthened (6)

I believe the answer is:

braced

I'm a little stuck... Click here to teach me more about this clue!

'strengthened' is the definition.
(bracing is a kind of strengthening)

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for braced that I've seen before include "made stronger" , "Prepared for a setback" , "Supported, gave firmness to" , "Ready for action" , "Stiff" .)

I've seen this clue in The Globe and Mail.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.