Thailand neighbor (4)
I believe the answer is:
laos
'thailand neighbor' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for laos that I've seen before include "part of Asia" , "South-east Asian republic, capital Vientiane" , "Indo-Chinese country" , "SE Asian country" , "Mountainous state in southeastern Asia" .)