assumption

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

authoritativeness, bossiness, dominance, high-handedness

condescension, disdain, scorn

chest-thumping, inflation, self-assertion, snobbery, snobbishness, snobbism, snootiness

attitude, cheek, cheekiness, impertinence, impudence, sauciness

boastfulness, bombast, bravado, strut, swagger, triumphalism, vaingloriousness, vainglory

cockiness, complacence, conceit, egoism, egotism, pride, pridefulness, self-assumption, self-centeredness, self-complacency, self-conceit, self-content, self-contentment, self-opinion, self-partiality, self-satisfaction, smugness, swelled head, vanity

superiority complex