Outstanding group in charge (7)
I believe the answer is:
classic
'outstanding' is the definition.
(thesaurus)
'group in charge' is the wordplay.
'group' becomes 'class' (class is a kind of group).
'in charge' becomes 'ic' (abbreviation for 'in charge').
'class'+'ic'='CLASSIC'
(Other definitions for classic that I've seen before include "Literary masterpiece" , "Relating to early Greek and Latin writers" , "Of the highest order - the Derby, for example" , "Timeless-quality work; a race" , "Judged over a long period to be of high quality" .)