Why a report is unusually commendable (12)
I believe the answer is:
praiseworthy
'commendable' is the definition.
(I know that commendable can be written as praiseworthy)
'why a report is unusually' is the wordplay.
'unusually' indicates an anagram.
'why'+'a'+'report'+'is'='whyareportis'
'whyareportis' anagrammed gives 'PRAISEWORTHY'.
(Other definitions for praiseworthy that I've seen before include "Laudable" , "Deserving of approval" , "Admirable" , "Commendable" .)