presume

If you presume something, you believe that it is true without evidence.

Example: The boy has been missing for a week, and is presumed dead.

If you presume to do something, you do it though it is rude or wrong.

Example: I wouldn't presume to go to the party without an invitation.

If x presumes y, then x requires y and builds on it.

Example: This books presumes a basic understanding of English grammar.