Ref has trouble again (6)
I believe the answer is:
afresh
'again' is the definition.
(synonyms)
'ref has trouble' is the wordplay.
'trouble' indicates anagramming the letters.
'ref'+'has'='refhas'
'refhas' is an anagram of 'AFRESH'.
(Other definitions for afresh that I've seen before include "In a new way" , "Newly" , "Academy award" , "Anew, from the beginning" , "In a different way" .)