Completely blooming accurate (8)
I believe the answer is:
outright
'completely' is the definition.
(thesaurus)
'blooming accurate' is the wordplay.
'blooming' becomes 'out' (I've seen this in other clues).
'accurate' becomes 'right' ('right' is associated in meaning with 'accurate').
'out'+'right'='OUTRIGHT'
(Other definitions for outright that I've seen before include "Unreservedly" , "Without qualification" , "Completely and openly - say a win" , "straight away" , "without qualifications" .)