Climbing around branch (4)
I believe the answer is:
limb
'branch' is the definition.
(I know that limb is a type of branch)
'climbing around' is the wordplay.
'around' indicates a hidden word.
'LIMB' is hidden within 'climbing'.
(Other definitions for limb that I've seen before include "Substantial branch from a tree trunk" , "Eg, arm, leg" , "Tentacle" , "Branch - member" , "as part of plane, say" .)