Unaccounted (adjective)

1. Not recorded or explained.
2. Not having been considered or taken into account.

Origin:

Late middle english (in the sense "not accounted for, without explanation"): from un- (expressing negation) + accounted, past participle of account.

Examples:

1. There were unaccounted losses from the recent stock market crash.
2. The government has promised to investigate the unaccounted expenditures.
3. The unaccounted income was finally discovered hidden in a secret bank account.
4. An unaccounted number of refugees have disappeared while trying to cross the border.
5. The unaccounted time was spent on developing a new project.