Lawless Moab -- one country that's evil (11)
I believe the answer is:
abomination
'evil' is the definition.
(thesaurus)
'lawless moab one country' is the wordplay.
'lawless' indicates anagramming the letters.
'one' becomes 'i' (Roman numeral).
'country' becomes 'nation' ('nation' can be a synonym of 'country').
'moab' anagrammed gives 'abom'.
'abom'+'i'+'nation'='ABOMINATION'
'that's' acts as a link.
(Other definitions for abomination that I've seen before include "Action that is vile" , "Feeling of hatred or disgust" , "Cause of hatred or disgust" .)