Flier with a tail (4)
(Other definitions for comet that I've seen before include "Celestial body with luminous tail" , "Rudolph's companion" , "high-flier" , "body found in space" , "High-flyer" .)
'flier with a tail' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for kite that I've seen before include "Flying toy or kind of hawk" , "A flying toy or sea bird" , "Toy that flies on end of string" , "Toy; aircraft (dated)" , "It flies with string attached" .)