This rep used to be a bohemian (7)
I believe the answer is:
hipster
'a bohemian' is the definition.
(I've seen this before)
'this rep used' is the wordplay.
'used' indicates an anagram.
'this'+'rep'='thisrep'
'thisrep' with letters rearranged gives 'HIPSTER'.
'to be' is the link.
(Other definitions for hipster that I've seen before include "Fashionable person" , "Bohemian" , "Cool dude" , "kind of pants" , "jazz he likes" .)