English Reference
Noun

investigator

n. countable
C1 Advanced Oxford US /ˌɪnˈvɛstəˌɡeɪtɝ/ UK /ɪnvˈɛstɪɡˌeɪtɐ/ in·ves·ti·ga·tor UK spelling investigator's, investigator's

n.a person whose job is to find out the truth about something, like a crime or a scientific problem. They look for clues and ask questions to solve a mystery.

n.a person who carries out a formal inquiry or systematic examination to uncover facts or determine the cause of an event. Often used in legal, scientific, or journalistic contexts.


SIMPLE

The lead investigator found a new clue at the scene.

CONTEXTUAL

The insurance company sent an investigator to check the damage before paying for the repairs.

COMPLEX

Following the sudden collapse of the bridge, a federal investigator was appointed to determine whether the failure was due to poor maintenance or a structural design flaw.

Usage

Commonly modified by adjectives like 'lead', 'private', or 'principal' to specify the person's rank or field.

Usage principal investigator

A preliminary report by US investigators says an engine fan blade broke on last month's flight from Greece to Germany.

BBC News· 13 Aug 2026

Broken engine parts were responsible for shattering a window on a Ryanair plane, causing a passenger to be partly sucked out mid-flight in July, US investigators have said.

The Guardian· 14 Aug 2026

Common in science writing


Attested in the mid‐16th century; from Latin investigator, from investigare, equivalent to investigate + -or.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin Latin investigator
Level C1 · Advanced
Frequency Frequent
Updated