Bomb thrown by a soldier (7)
(Other definitions for grenade that I've seen before include "Small bomb thrown by hand" , "hand-held missile" , "ultimate weapon" , "Small explosive that is thrown" , "One might go off" .)
(Other definitions for hand grenade that I've seen before include "Small thrown bomb" , "Small explosive device for throwing" , "Small explosive device used in close combat" , "Military explosive" , "Tree with edible nuts" .)