Five braces exercise stunted climber's grip (7)
I believe the answer is:
tendril
'climber's grip' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'five braces exercise stunted' is the wordplay.
'five braces' becomes 'ten' (I can't explain this - if you can you should believe this answer much more).
'exercise' becomes 'drill' (military exercise).
'stunted' means to remove the last letter (the word is shorter than it usually is).
'drill' with its final letter taken off is 'dril'.
'ten'+'dril'='TENDRIL'
Can you help me to learn more?
(Other definitions for tendril that I've seen before include "Natural thread climbing plants produce to attach to a support" , "Clinging part of a plant" , "Plant's climbing aid" , "Twisted lock of hair" , "Climbing plant's supporter" .)