Seen in Soho: Greek giant (4)
I believe the answer is:
ogre
'giant' is the definition.
(I know that ogre is a type of giant)
'seen in soho greek' is the wordplay.
'seen in' indicates a hidden word.
'OGRE' is hidden in the letters of 'soho greek'.
(Other definitions for ogre that I've seen before include "Giant of folklore who liked to eat humans" , "Terrifying giant" , "Terrifying person" , "Bugbear" , "Giant of folklore who ate humans" .)