A type of guided missile (6)
I believe the answer is:
exocet
'a type of guided missile' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for exocet that I've seen before include "which may be guided to hit ship" , "Type of guided missile" , "Tactical missile" , "Weapon" , "Subsonic, low-altitude missile" .)