Incommunicado (adjective)

1. Not in contact or not communicating with others.
2. Not able to be contacted or not able to communicate.

Origin:

This word is derived from spanish word "incomunicado" which is formed by the combination of the prefix "in-" meaning "not" and the word "comunicado" meaning "communicated" or "in touch".

Examples:

1. He was held incommunicado for several days and was not allowed to see a lawyer.
2. The ship was lost at sea and its crew was incommunicado.
3. She went incommunicado and didn't tell anyone where she was going.
4. The prisoner was kept incommunicado and was not allowed any visitors.
5. The hikers were incommunicado and lost contact with civilization for weeks.