One who turns away a relation in trouble? (9)
I believe the answer is:
alienator
'one who turns away' is the definition.
(someone who alienates)
'a relation in trouble?' is the wordplay.
'in trouble?' is an anagram indicator (I've seen 'in trouble' mean this).
'relation' anagrammed gives 'lienator'.
'a'+'lienator'='ALIENATOR'
(Other definitions for alienator that I've seen before include "Causer of estrangement" , "one who repels" , "Off-putting type" .)