Unstated (adjective)

1. Not stated explicitly or in detail; implicit.
2. Not made public or officially announced.

Origin:

Late 16th century: from un-1 + the verb state.

Examples:

1. An unstated assumption of the argument.
2. The unstated purpose of the meeting.
3. The unstated rule of the game.
4. The unstated policy of the government.
5. The unstated objective of the campaign.