Terribly reviled about nothing, initially seeming villains (9)
I believe the answer is:
evildoers
'villains' is the definition.
The answer and definition can be both people as well as being plural nouns.
Maybe you can see an association between them that I don't see?
'terribly reviled about nothing initially seeming' is the wordplay.
'terribly' is an anagram indicator.
'about' says to put letters next to each other.
'nothing' becomes 'O' (looks like zero - 0).
'initially' suggests taking the first letters.
The initial letter of 'seeming' is 's'.
'reviled' put after 'o' is 'oreviled'.
'oreviled' with letters rearranged gives 'evildoer'.
'evildoer'+'s'='EVILDOERS'
Can you help me to learn more?
(Another definition for evildoers that I've seen is " People acting wickedly".)