Minor yet revolting atrocity (8)
I believe the answer is:
enormity
'atrocity' is the definition.
(I know that enormity is a type of atrocity)
'minor yet revolting' is the wordplay.
'revolting' indicates an anagram.
'minor'+'yet'='minoryet'
'minoryet' with letters rearranged gives 'ENORMITY'.
(Other definitions for enormity that I've seen before include "Great wickedness or huge size" , "major crime" , "Vastness - great crime" , "Outrageous act" , "horror" .)