Scrutinize, scan, inspect, examine, audit can all mean to look at or over critically and searchingly. The same distinctions in implications and connotations are observable in their corresponding nouns scrutiny, scanning, inspection, examination, and audit.
Scrutinize and scrutiny imply close observation and attention to minute detail.
Scan and scanning are usually employed in reference to something that is surveyed from point to point; the terms may imply careful observation or study but sometimes imply the opposite and suggest a cursory glancing from one point to another; thus, to scan the newspaper each morning may admit of either interpretation.
Only a context can make the implication clear.
Inspect and inspection in general use often imply little more than a careful observation, but in legal, military, governmental, and industrial use they imply a searching scrutiny for possible errors, defects, flaws, or shortcomings.
Examine (see also ASK 1 ) and examination imply a close scrutiny or investigation to determine the facts about a thing or the real nature, character, or condition of a thing or to test a thing’s quality, validity, truth, or functioning.
Audit, as verb or noun, implies a searching examination of accounts in order to determine their correctness. In its extended sense audit often carries a suggestion of a final accounting.