Unkind (6)
'unkind' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for cold-hearted that I've seen before include "Indifferent" , "Unfeeling" , "Unkind" .)
(Other definitions for horrid that I've seen before include "Awful" , "Repellent" , "Frightful" , "Repulsive" , "Dreadful" .)
'unkind' is the definition.
(thesaurus)
This is all the clue.
(Other definitions for ill that I've seen before include "Hardly - sick" , "Off-colour" , "reduced state" , "Harmful" , "trouble" .)