Press one mobile to get an answer (8)
I believe the answer is:
response
'an answer' is the definition.
(synonyms)
'press one mobile' is the wordplay.
'mobile' indicates anagramming the letters.
'press'+'one'='pressone'
'pressone' with letters rearranged gives 'RESPONSE'.
'to get' is the link.
(Other definitions for response that I've seen before include "Sees porn (anag) - answer" , "Press one for a reply" , "Acknowledgement" , "'Answer, reply (8)'" , "comeback" .)