Kid lies about hostile feeling (7)
I believe the answer is:
dislike
'hostile feeling' is the definition.
(feeling of hostility to someone)
'kid lies about' is the wordplay.
'about' indicates anagramming the letters.
'kid'+'lies'='kidlies'
'kidlies' is an anagram of 'DISLIKE'.
(Other definitions for dislike that I've seen before include "Object to" , "Feel distaste for (something)" , "Fell aversion or antipathy" , "Don't take to" , "Can't stand" .)