Forgive a second rate answer (7)
I believe the answer is:
absolve
'forgive' is the definition.
(absolving is a kind of forgiving)
'a second rate answer' is the wordplay.
'second rate' becomes 'b'.
'answer' becomes 'solve' ().
'a'+'b'+'solve'='ABSOLVE'
(Other definitions for absolve that I've seen before include "Set free from guilt" , "Exonerate" , "Grant pardon for" , "Cleanse" , "Declare (someone) free of guilt" .)