One forced to join up — that sounds chilling (7)
I believe the answer is:
draftee
'one forced to join up' is the definition.
(someone drafted into the army)
'sounds chilling' is the wordplay.
'sounds' indicates a 'sounds like' (homophone) clue.
'chilling' becomes 'draughty' (chill can mean a draught).
'draughty' is a homophone of 'DRAFTEE'.
'that' is the link.
(Other definitions for draftee that I've seen before include "Rookie" , "Soldier, perhaps unwilling" , "American military conscript" , "US conscript" , "one brought into service" .)