Monster discovered in bog recently (4)
I believe the answer is:
ogre
'monster' is the definition.
('ogre' can be a synonym of 'monster')
'discovered in bog recently' is the wordplay.
'discovered' indicates a hidden word (remove the letters covering the answer in the clue).
'OGRE' is hidden in the letters of 'in bog recently'.
(Other definitions for ogre that I've seen before include "Fierce giant" , "Fairy-tale creature" , "Terrifying man" , "Has a monstrous role" , "The giant is some goer" .)