Agents infiltrating Laos ruins but avoiding others (7)
I believe the answer is:
asocial
'avoiding others' is the definition.
(I've seen this before)
'agents infiltrating laos ruins' is the wordplay.
'agents' becomes 'CIA' (Central Intelligence Agency).
'infiltrating' is an insertion indicator.
'ruins' is an anagram indicator.
'laos' anagrammed gives 'asol'.
'cia' inserted inside 'asol' is 'ASOCIAL'.
'but' is the link.
(Other definitions for asocial that I've seen before include "lacking friendly instincts" , "Inconsiderate to others" , "without friends" , "Solitary" , "Not fond of company, perhaps inconsiderate" .)