detective
detective (dĭ-tĕkʹtĭv) noun
A person, usually a member of a police force, who investigates crimes and obtains evidence or information.
adjective
1. Of or relating to detectives or their work: detective novels.
2. Suited for or used in detection.
Word History: The first detective may have come into existence before the word itself. C. Auguste Dupin, Edgar Allan Poe's hero in "The Murders in the Rue Morgue," which is considered the world's first real detective story, was introduced to the world in 1841. Nine years later we find the first recorded instance of the word detective, although the phrases detective police and detective policeman, from which it was shortened, are recorded first in 1843. Hence, Dupin precedes all recorded instances of detective, just as he precedes all other detectives.