Moreover, it's from Laos (4)
I believe the answer is:
also
'moreover' is the definition.
('also' can be a synonym of 'moreover')
'from laos' is the wordplay.
'from' is an anagram indicator (from the letters).
'laos' is an anagram of 'ALSO'.
'it's' acts as a link.
(Other definitions for also that I've seen before include "Old" , "in accompaniment" , "Furthermore" , "'Besides, moreover (4)'" , "revolutionary a part for Yugoslavia" .)