Villainous ogre madly going round the bend (5)
I believe the answer is:
rogue
'villainous ogre madly going round the bend' is the definition.
I can't tell whether this definition defines the answer.
'ogre madly going round the bend' is the wordplay.
'madly' is an anagram indicator.
'going round' means one lot of letters goes inside another (some letters go around others).
'the bend' becomes 'U' (a U-bend is a kind of bend - pipe under sink).
'ogre' anagrammed gives 'roge'.
'roge' enclosing 'u' is 'ROGUE'.
Can you help me to learn more?
(Other definitions for rogue that I've seen before include "Diseased plant" , "Bad guy" , "Stray" , "Charlatan" , "Baddie" .)