Egyptian king admits slip, going around in tank top (6)
I believe the answer is:
turret
'tank top' is the definition.
(I've seen this in another clue)
'egyptian king admits slip going around' is the wordplay.
'egyptian king' becomes 'tut' (nickname of Tutankhamun).
'admits' is an insertion indicator (to admit is to allow in).
'slip' becomes 'err' (to err is to make an error).
'going around' says the letters should be written in reverse.
'tut' going around 'err' is 'terrut'.
'terrut' backwards is 'TURRET'.
'in' acts as a link.
(Other definitions for turret that I've seen before include "One of two rings" , "Small tower on defensive wall - or tank" , "Small tower projecting from a wall of a castle" , "Tower-like projection on defensive wall" , "Keep feature" .)