An investigator is someone who carries out investigations, especially as part of their job. They have also hired investigators to find her. Collins COBUILD Advanced Learner’s Dictionary. Copyright © HarperCollins Publishers Collins English Dictionary. Copyright © HarperCollins Publishers Webster’s New World College Dictionary, 4th Edition.

The accident investigator observed that unexpected events, such as user slips and mode errors, are commonly considered as human errors. Physicians in the role of clinical investigator often solicit their patients to become part of a research study. He, a career criminal investigator, is the youngest-ever to hold that post.

Definition of investigator noun from the Oxford Advanced Learner's Dictionary a person who examines a situation such as an accident or a crime to find out the truth Questions about grammar and vocabulary? Find the answers with Practical English Usage online, your indispensable guide to problems in English.

Every crime novel has an investigator, someone whose job it is to discover the truth. Not all investigators solve crimes, but to be an investigator you need to work hard to figure things out. A private investigator knocks at your door. Do you let him in? He probably only wants to ask questions, because that’s what investigators do: they research.