unauthorized
adj.adj. done without official permission. You use this to describe actions or people that do not have the right to be in a place or do a certain thing.
adj. lacking official approval or legal permission. Often used in legal, security, or administrative contexts to describe access or activities that violate established rules.
The security guard stopped an unauthorized visitor at the gate.
The bank blocked the transaction because it appeared to be an unauthorized attempt to move funds.
The investigation revealed that several employees had gained unauthorized access to the confidential database over a period of six months, leading to a significant data breach.
From un- + authorized.
Typically placed before the noun it modifies; often follows a linking verb in formal reports.