Monstrous giants (5)
I believe the answer is:
ogres
'monstrous giants' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ogres that I've seen before include "Giant types" , "Monsters can be goers" , "Bugbears" , "She-giant of fairy tale" , "Giants in fairytales" .)