Siamese connection, we hear (4)
I believe the answer is:
thai
'siamese' is the definition.
(I know that siamese can be written as Thai)
'connection we hear' is the wordplay.
'connection' becomes 'tie' (tie is a kind of connection).
'we hear' indicates a 'sounds like' (homophone) clue.
'tie' sounds like 'THAI'.
(Other definitions for thai that I've seen before include "Morte d'16author" , "Easterner" , "Native to Phuket, for example" , "One from Bangkok" , "countryman" .)