Ogre makes English discovery outside (5)
I believe the answer is:
fiend
'ogre' is the definition.
(I know that ogre can be written as fiend)
'english discovery outside' is the wordplay.
'english' becomes 'E' (abbreviation as in OED).
'discovery' becomes 'find' (synonyms).
'outside' means one lot of letters goes inside another (some letters go outside others).
'e' put inside 'find' is 'FIEND'.
'makes' acts as a link.
(Other definitions for fiend that I've seen before include "Devilish person" , "monster" , "Demon; cruel person" , "Wicked and inhuman person" , "Evil supernatural being" .)