private detective
noun /ˌpraɪvət dɪˈtektɪv/
/ˌpraɪvət dɪˈtektɪv/
(also private investigator)
(also informal private eye)
- a detective who is not in the police, but who can be employed to find out information, find a missing person, follow somebody, etc.
- She hired a private detective to follow her husband.