All these words mean to look something over or inquire into it, usually for a definite purpose. Examine is the general word; it can refer to a cursory look or a thorough study of all details. Investigate , scrutinize and inspect mean to examine thoroughly, but their connotations vary. To investigate is to make a methodical, searching inquiry into a complex situation in an effort to uncover the facts. Scrutinize suggests examining critically and with painstaking attention to detail: a printer scrutinizing a photographic transparency for specks of dust or imperfections. Inspect usually implies that the object of one’s attention is being critically compared to a standard of excellence, quality or the like, with a view towards noting discrepancies or deficiencies in the former: firemen inspecting an abandoned warehouse for potential fire hazards; a sergeant inspecting the rifles of his men. One may examine , scrutinize or inspect a person, an inanimate object or a situation; investigate is usually applied to situations or events, except in the case of formal inquiries into the lives or actions of a person, because he is suspected of a crime or because he has applied for a job of a particularly sensitive nature: to investigate the background of a potential member of the secret service.

• The detective investigating the murder case examined the body, inspected the scene of the crime, and scrutinized the weapon for clues.

To audit is to examine accounts or records. Thus, to justify an increase in advertising rates, a magazine publisher may engage an outside firm to audit the circulation figures.

Scan is a word that is undergoing a complete reversal of meaning. Its former meaning – to examine closely and analytically – is still valid, but is now applied chiefly to analysis of poetic metre: to scan Virgil. More frequently now, scan means to glance quickly at something to get the gist of it: to scan a newspaper by glancing at the headlines.