foreign secret agent

агент негласного апарату розвідувального органу іноземної держави (про розвідку / термін спецслужб)

secret agent intelligence

agent / agent network / agents

CW agent (chemical warfare agent)

obscurant agent (vision-restricting agent)

damage agent / damaging agent

secret (security classification)

secret

Secret Intelligence Service (SIS) / Military Intelligence, Section 6 (MI6)

secret internet protocol router network (SIPRNET)

secret service

top secret (security classification)

top secret

state secret

be drawn from secret intelligence

be marked top secret

give away the secret by careless talk

clear secret

clearance for top secret work

secret clearance

secret defense service

secret language

secret post

secret qualification clearance

secret security clearance

secret service

secret text

secret weapon

Common Foreign and Security Policy (CFSP, EU)

foreign duty

foreign instrumentation signals

foreign intelligence

Foreign Intelligence Service (SVR)