Civilized leader had bloody class (8)
I believe the answer is:
category
'class' is the definition.
(I know that category is a metaclass)
'civilized leader had bloody' is the wordplay.
'leader' says to take the initial letters.
'had' becomes 'ate' ('have' can mean 'eat').
'bloody' becomes 'gory' (similar in meaning).
The first letter of 'civilized' is 'c'.
'c'+'ate'+'gory'='CATEGORY'
(Other definitions for category that I've seen before include "Class or order" , "Class of grey-coat" , "Logical grouping" , "Classification of grey-coat" , "Kind" .)