Give strength to a couple (5)
I believe the answer is:
brace
'to a couple' is the definition.
(brace can mean a pair of something)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for brace that I've seen before include "double" , "Pair - strut" , "Two - supporter" , "Carpenter's tool for a pair" , "Pair; hand drill" .)