Indifferent military officer on date (4)
I believe the answer is:
cold
'indifferent' is the definition.
(thesaurus)
'military officer on date' is the wordplay.
'military officer' becomes 'col' (colonel).
'on' says to put letters next to each other (in a down clue, letters appear on others).
'date' becomes 'd' (abbreviation e.g. dob - date of birth).
'col'+'d'='COLD'
(Other definitions for cold that I've seen before include "Biting" , "Lacking affection" , "At low temperature" , "Mild viral infection, very common" , "Unfriendly" .)