assertion

1 a solemn and often public declaration of the truth or existence of something the assertion that all men have certain unalienable rights is set forth in the Declaration of Independence Synonyms affirmation, protestation, asseveration, avouchment, avowal, claim, declaration, insistence, professionRelated Words allegation; announcement, proclamation, pronouncement; argument, justification, rationalization, reason; confirmation, reaffirmation, reconfirmation, vindicationNear Antonyms disclaimer; challenge, dispute, question; confutation, disproof, rebuttal, refutation; contradiction, denial, negationAntonyms disavowal

2 an idea or opinion that is put forth in a discussion or debate made the unlikely assertion that gravity affects light Synonyms argument, contention, thesisRelated Words conjecture, guess, hunch, hypothesis, speculation, surmise, theory; proposal, proposition; assumption, presupposition, supposition; position, stand; case, explanation, rationale, reason