Untraceable (adjective)

Not able to be traced or located; unable to be found or followed.

Origin:

Late 19th century; formed from the prefix un- and the verb "trace".

Examples:

1. The thief's money was untraceable.
2. The assassin's movements were untraceable.
3. The hacker's IP address was untraceable.
4. The criminal's identity was untraceable.
5. The source of the contamination was untraceable.