assert

American Heritage® Dictionary of the English Language, Fourth Edition

1. v. To state or express positively; affirm: asserted his innocence.
2. v. To defend or maintain (one's rights, for example).
3. idiom. assert oneself To act boldly or forcefully, especially in defending one's rights or stating an opinion.

Century Dictionary and Cyclopedia

1. To bring (into freedom); set (free).
2. To vindicate, maintain, or defend by words or measures; support the cause or claims of; vindicate a claim or title to: now used only of immaterial objects or reflexively: as, to assert our rights and liberties; he asserted himself boldly.
3. To state as true; affirm; asseverate; aver; declare.
4. Syn. 2. Assert, Defend, Maintain, Vindicate, Assert supports a cause or claim aggressively: its meaning is well brought out in the expression, assert yourself; that is, make your influence felt. To defend is primarily to drive back assaults. To maintain is to hold up to the full amount, defending from diminution: as, to maintain the ancient customs, liberties, rights. To vindicate is to rescue, as from diminution, dishonor, or censure: as, to “vindicate the ways of God to man,”
5. Assert, Affirm, Declare, Aver, Asseverate (see declare), allege, protest, avow, lay down. (See protest.) Assert seems to expect doubt or contradiction of what one says. Affirm strengthens a statement by resting it upon one's reputation for knowledge or veracity: as, “she constantly affirmed that it was even so,” Acts xii. 15. Declare makes public, clear, or emphatic, especially against contradiction. Aver is positive and peremptory. Asseverate is positive and solemn.

Wiktionary

1. n. computer science an assert statement; a section of source code which tests whether an expected condition is true.
2. v. To declare with assurance or plainly and strongly; to state positively.
3. v. To use or exercise and thereby prove the existence of.
4. v. 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.
5. v. computer science to make true; to make equal to 1.

GNU Webster's 1913

1. v. To affirm; to declare with assurance, or plainly and strongly; to state positively; to aver; to asseverate.
2. v. Obs. or Archaic To maintain; to defend.
3. v. To maintain or defend, as a cause or a claim, by words or measures; to vindicate a claim or title to.

WordNet 3.0

1. v. assert to be true
2. v. state categorically
3. v. to declare or affirm solemnly and formally as true
4. v. insist on having one's opinions and rights recognized