An idea that is taken to be true on the basis of probability. The presumption that the meeting would be canceled was incorrect.
Behavior perceived as arrogant, disrespectful, and transgressing the limits of what is permitted or appropriate. His presumption in speaking for the entire group was not well received.
A legal inference or assumption that a fact exists, based on the known or proven existence of some other fact or group of facts. The presumption of innocence is a fundamental principle in criminal law.