Undetected (adjective)

Not discovered or noticed; not detected.

Origin:

From the prefix un- meaning not and the past participle of the verb detect, meaning to discover or notice.

Examples:

1. The thief was able to steal the jewels undetected.
2. The disease was undetected for months, which allowed it to spread.
3. The error in the code went undetected until it caused a crash.
4. The spy operated undetected within the enemy's ranks for years.
5. The bug was undetected by the exterminator, so it continued to thrive.