Last Egyptian leader to enter conflict (4)
I believe the answer is:
wear
'last' is the definition.
(wearing is a kind of lasting)
'egyptian leader to enter conflict' is the wordplay.
'leader' indicates taking the first letters.
'to enter' is an insertion indicator.
'conflict' becomes 'war' (war is a kind of conflict).
The first letter of 'egyptian' is 'e'.
'e' placed into 'war' is 'WEAR'.
(Other definitions for wear that I've seen before include "Damage from use" , "Be clothed in" , "Carry the burden" , "Durham's river - erosion" , "Have on the body as clothes or ornaments" .)