Spies found in a men's toilet (6)
I believe the answer is:
agents
'spies' is the definition.
(I've seen this before)
'a men's toilet' is the wordplay.
'men's toilet' becomes 'gents'.
'a'+'gents'='AGENTS'
'found in' is the link.
(Other definitions for agents that I've seen before include "travelling salesmen" , "Representatives" , "They do business on behalf of others" , "Spies" , "They act for others" .)