Noah Webster's New International Dictionary of the English Language

1. (v. t.) To affirm; to declare with assurance, or plainly and strongly; to state positively; to aver; to asseverate.

2. (v. t.) To maintain; to defend.

3. (v. t.) To maintain or defend, as a cause or a claim, by words or measures; to vindicate a claim or title to; as, to assert our rights and liberties.