assert

UK: /əˈsɜː^rt/ US: /əˈsɝt/ ,(ə sûrt′)

WordReference Random House Learner's Dictionary of American English © 2025

as•sert /əˈsɜrt/   v. [~ + object]

1. to state strongly or positively;
   declare strongly:
   asserted his innocence.
   [~ + (that) clause]
   asserted that he was innocent of the crime.
2. to make a claim to:
   Minorities are now asserting their right to be heard.

Idioms

3. Idioms assert oneself, to claim one's rights or declare one's views firmly.

WordReference Random House Unabridged Dictionary of American English © 2025

as•sert  (ə sûrt′), v.t. 

1. to state with assurance, confidence, or force;
   state strongly or positively;
   affirm;
   aver:
   He asserted his innocence of the crime.
2. to maintain or defend (claims, rights, etc.).
3. to state as having existence;
   affirm;
   postulate:
   to assert a first cause as necessary.
4. assert oneself, to insist on one's rights, declare one's views forcefully, etc.:
   The candidate finally asserted himself about property taxes.

• Latin assertus joined to, defended, claimed (past participle of asserere), equivalent. to as- as- + ser- (see series) + -tus past participle suffix
• 1595–1605

as•sert′er, as•ser′tor, n. 
as•sert′i•ble, adj. 
Synonyms

• 1. asseverate, avow, maintain. See declare. 
• 2. uphold, support. See maintain. 

Antonyms

• 1. deny.

Collins Concise English Dictionary © HarperCollins Publishers::

assert / əˈsɜːt/ verb (transitive)

1. to insist upon (rights, claims, etc)
2. (may take a clause as object) to state to be true; declare categorically
3. to put (oneself) forward in an insistent manner

Etymology: 17th Century: from Latin asserere to join to oneself, from serere to join

asˈserter, asˈsertor noun