Respond concerning deed
I believe the answer is:
re-act
'respond' is the definition.
(I've seen this before)
'concerning deed' is the wordplay.
'concerning' becomes 're'.
'deed' becomes 'act' (I've seen this before**).
're'+'act'='RE-ACT'
(Other definitions for re-act that I've seen before include "Trace (anag)" , "Respond -- reply" , "Respond (to a stimulus)" , "Hit back" , "Show a response to something" .)