Perform for free? (9)
I believe the answer is:
discharge
I believe this is a double definition.
'perform' is the first definition.
(I've seen this before)
'free?' is the second definition.
(thesaurus)
'for' acts as a link.
(Other definitions for discharge that I've seen before include "unload" , "cashier" , "Let off - set free" , "empty" , "Put out" .)