Strengthen bird after suffering gout (7)
I believe the answer is:
toughen
'strengthen' is the definition.
(I know this)
'bird after suffering gout' is the wordplay.
'bird' becomes 'hen' (hen is a kind of bird).
'after' says to put letters next to each other.
'suffering' indicates an anagram.
'gout' with letters rearranged gives 'toug'.
'hen' after 'toug' is 'TOUGHEN'.
(Other definitions for toughen that I've seen before include "Make more resilient" , "Add resistance to" , "Strengthen, season" , "Harden, strengthen" , "Make stronger and hardier" .)