Glorious blues I'm playing (7)
I believe the answer is:
sublime
'glorious' is the definition.
(similar in meaning)
'blues i'm playing' is the wordplay.
'playing' is an anagram indicator.
'blues'+'im'='bluesim'
'bluesim' with letters rearranged gives 'SUBLIME'.
(Other definitions for sublime that I've seen before include "Awe-inspiring - exalted" , "Of great excellence or beauty, awe-inspiring" , "Exalted; awesome" , "Glorious; supreme" , "Exalted, lofty" .)