Presumption (noun)

1. An attitude or belief that something is true or probable without sufficient evidence.
2. An attitude or assumption that takes liberties or exceeds the bounds of propriety.
3. A fact or principle assumed in a given situation, from which further inferences can be drawn.

Origin:

Late middle english: from old french presumpcion, from latin praesumptio(n-), from praesumere "take for granted".

Examples:

1. She acted with presumption when she took his seat without asking.
2. The judge overturned the jury's verdict on the grounds of insufficient evidence, challenging the prosecution's presumptions.
3. The astronomer made a presumption that the new planet was in a stable orbit.
4. His presumptions about her character were completely wrong.
5. The court's ruling was based on a legal presumption that the defendant was guilty until proven innocent.