Shrewd like Egyptian king, last of line (6)
I believe the answer is:
astute
'shrewd' is the definition.
(I know that shrewd can be written as astute)
'like egyptian king last of line' is the wordplay.
'like' becomes 'as'.
'egyptian king' becomes 'tut' (nickname of Tutankhamun).
'last of' indicates one should take the final letters.
The last letter of 'line' is 'e'.
'as'+'tut'+'e'='ASTUTE'
(Other definitions for astute that I've seen before include "Peerceptive" , "Statue (anag)" , "Subtle" , "intelligent" , "Smart and canny" .)