Unfriendly daughter isn't accepting thanks (7)
I believe the answer is:
distant
'unfriendly' is the definition.
(thesaurus)
'daughter isn't accepting thanks' is the wordplay.
'daughter' becomes 'd'.
'accepting' indicates putting letters inside.
'thanks' becomes 'ta' (UK informal version of 'thank you').
'isnt' going around 'ta' is 'istant'.
'd'+'istant'='DISTANT'
(Other definitions for distant that I've seen before include "Unfriendly; far off" , "Absent - coming from a far-away place" , "Far away" , "Far from - reserved" , "Reserved - a long way off" .)