Possibly press one for an answer (8)
I believe the answer is:
response
'for an answer' is the definition.
(synonyms)
'possibly press one' is the wordplay.
'possibly' is an anagram indicator.
'press'+'one'='pressone'
'pressone' is an anagram of 'RESPONSE'.
(Other definitions for response that I've seen before include "Sees porn (anag) - answer" , "Reaction, reply" , "Answer - reaction" , "Press one for a reply" , "Answer - retort" .)