Distant, unsympathetic (5)
I believe the answer is:
This clue is a double definition.
'distant' is the first definition.
'unsympathetic' is the second definition.
(I've seen this in another clue)
(Other definitions for aloof that I've seen before include "Displaying supercilious reserve" , "Blood deficiency" , "Unpleasantly cold" , "Indifferent - by oneself" , "Standoffish like a fool" .)