unwritten

Human rights groups believe there is an unwritten agreement among the four neighbouring countries to allow each other's security forces to pursue dissidents over the border.

“Our team followed every written and unwritten rule, left no trace, and honored Yosemite’s accepted traditions.”

Her university has an unwritten rule that students must sign an employment contract or provide proof of internship within one year of graduation; otherwise, they won't receive a diploma.

Star Wars: Galaxy’s Edge arrives — and the rest is unwritten.

But Cloudflare argues AI breaks the unwritten agreement between publishers and crawlers.