25 entries under operative topic. ×

20
investigator(noun, person, plant, investigate, agent)
10
sleuth(noun, information, plant, watch, investigate)
8
snoop(noun, person, plant, agent)
7
scout(noun, verb, person, plant, watch)
4
agent(noun, plant, shadow, mole)
4
secret agent(noun, expression, idiom, plant, agent)
3
informer(noun, information, plant, agent)
2
emissary(noun, plant, watch, agent, spy)
2
patrol(noun, person, force, plant, bear)
1
foreign agent(noun, expression, plant, agent)
1
inside agent(noun, expression, plant, agent)
1
intelligencer(noun, plant, agent, informer)
1
lookout(noun, plant, watch, guard, agent)
1
mole(noun, plant, watch, agent, spy)
1
observer(noun, plant, watch, guard, agent)
1
picket(noun, plant, watch, guard, agent)
1
plant(noun, agent, informer, mole)
1
secret service(noun, expression, plant, agent)
1
sleeper(noun, plant, agent, informer)
1
spook(noun, plant, agent, informer)
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APASmart Define. (2015). detective thesaurus. Retrieved September 27, 2026, from https://smartdefine.org/detective/thesaurus/synonyms
ChicagoSmart Define. 2015. "detective thesaurus" https://smartdefine.org/detective/thesaurus/synonyms (accessed September 27, 2026).
HarvardSmart Define 2015, detective thesaurus, Smart Define, viewed 27 September, 2026, <https://smartdefine.org/detective/thesaurus/synonyms>.
MLASmart Define. "detective thesaurus" 14 April 2015. Web. 27 September 2026. <https://smartdefine.org/detective/thesaurus/synonyms>