presumption

arrogance, assurance, cockiness, confidence, hardihood, overconfidence, sanguinity, self-assurance, self-confidence

discourteousness, disrespect, impertinence, impoliteness, impudence, incivility, inconsiderateness, inconsideration, insolence, rudeness, ungraciousness

back talk, sass

swagger, swash

hypothesis, proposition, theory, thesis

axiom, truism, verity

belief, canon, doctrine, dogma, gospel, law

precept, principle, rule, standard, tenet

basis, foundation, ground

conclusion, deduction, inference

affirmation, assertion, avouchment, declaration

dictum, ipse dixit