Ron means to become a Viking (8)
I believe the answer is:
norseman
'a viking' is the definition.
(I've seen this before)
'ron means to become' is the wordplay.
'to become' is an anagram indicator.
'ron'+'means'='ronmeans'
'ronmeans' is an anagram of 'NORSEMAN'.
(Other definitions for norseman that I've seen before include "one attacking north-east?" , "A viking, perhaps" , "invader" , "Scandinavian" .)