| spy(noun, person, plant, mole, sleeper) |
| emissary(noun, plant, express, agent, operative) |
| informant(noun, information) |
| informer(noun, plant, agent, operative, mole) |
| authority |
| exponent(noun, information) |
| reporter(noun, information) |
| secret agent(noun, expression, idiom, plant, agent) |
| agent(noun, plant, operative, informer, mole) |
| communicant |
| correspondent |
| courier(noun, messenger) |
| detective(noun, plant, agent, operative, informer) |
| double agent(noun, expression, plant, agent, operative) |
| espionage agent(noun, expression, plant, agent, operative) |
| foreign agent(noun, expression, plant, agent, operative) |
| inside agent(noun, expression, plant, agent, operative) |
| investigator(noun, plant, agent, operative, informer) |
| lookout(noun, plant, agent, operative, informer) |
| mole(noun, plant, agent, operative, informer) |