Level in educational establishment for male (7)
I believe the answer is:
uniform
'level' is the definition.
(thesaurus)
'educational establishment for male' is the wordplay.
'educational establishment' becomes 'uni' (I've seen this before).
'male' becomes 'm' (common abbreviation).
'uni'+'for'+'m'='UNIFORM'
'in' acts as a link.
(Other definitions for uniform that I've seen before include "Unvarying; livery" , "Unchanging, showing no variation" , "Military clothes" , "Consistent, unvarying" , "reluctant pupils may be forced to wear it" .)