Peer's son's strange answer (8)
I believe the answer is:
response
'answer' is the definition.
(I know that answer can be written as response)
'peer's son's strange' is the wordplay.
'strange' indicates an anagram.
'peer'+'sons'='peersons'
'peersons' with letters rearranged gives 'RESPONSE'.
(Other definitions for response that I've seen before include "Answer - retort" , "Preens so by way of answer" , "Reply, rejoinder" , "bid by partner" , "comeback" .)