assertion UK /əˈsɜːʃən/US /əˈsɜɹʃən/ noun6 •The act of asserting; positive declaration or averment. •Something which is asserted; a declaration; a statement asserted.You're a man of strong assertions! •A statement or declaration which lacks support or evidence.That's just a bare assertion. •A statement in a program asserting a condition expected to be true at a particular point, used in debugging. •The set of information that the statement preparer is providing in a financial statement audit. •Maintenance; vindication.the assertion of one's rights or prerogatives formsassertions