Egyptian serpent (3)
I believe the answer is:
asp
'egyptian serpent' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for asp that I've seen before include "creeper" , "Venomous snake" , "Reptile" , "It proved deadly for Cleopatra" , "the snake in Cleopatra''s bosom" .)