noun
detective; investigator; sleuth
Refers to a person who investigates cases, mysteries, missing people, infidelity, and similar matters; often used for private detectives as well as fictional detectives.
彼女は私立探偵に夫の行方を調べてもらった。
She had a private detective look into her husband's whereabouts.
この小説の主人公は若い探偵だ。
The protagonist of this novel is a young detective.
noun, noun or participle which takes 'suru', transitive verb
detective work; secret investigation; investigate secretly
As a noun this can refer to detective work or secret investigation. The する-verb use, as in 探偵する, is much less common in modern everyday Japanese than 調査する or 探る and can sound written or old-fashioned.
古い文章では、「敵情を探偵する」のように、ひそかに調べる意味で使われることがある。
In older writing, expressions like 敵情を探偵する may be used to mean investigating the enemy's situation secretly.