Thailand's neighbor (4)
I believe the answer is:
laos
'thailand's 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 "South-east Asian republic, capital Vientiane" , "Landlocked state in southeastern Asia" , "Landlocked south-east Asian country" , "Republic in southeastern Asia" , "part of Asia" .)