Asian couple in conversation (4)
I believe the answer is:
thai
'asian' is the definition.
(from Thailand)
'couple in conversation' is the wordplay.
'couple' becomes 'tie' (both can mean to join).
'in conversation' indicates a 'sounds like' (homophone) clue.
'tie' is a homophone of 'THAI'.
(Other definitions for thai that I've seen before include "Asian language" , "nationality" , "is concerned with an eastern country" , "Easterner" , "National" .)