presumptuous (adj.)

mid-14c., "arrogant, overweening, impertinent, going beyond the limits of propriety or good sense in thought or conduct," from Old French presuntuex, presontuos, presumptueuse (12c.; Modern French présomptueux) and directly from Late Latin praesumptuosus "full of boldness," a variant of praesumptiosus, from past participle stem of Latin praesumere "anticipate," in Late Latin, "assume" (see presume). Related: Presumptuously; presumptuousness.