- The definition of presumptuous is taking things for granted or being overconfident.
An example of presumptuous is assuming that you will win the city wide spelling bee just because you scored 100% on your last spelling quiz.
Origin of presumptuousMiddle English ; from Old French presunteux ; from Late Latin praesumptuosus ; from Classical Latin praesumptus: see presumption
Origin of presumptuousMiddle English, from Old French presumptueux, from Late Latin praesūmptuōsus, variant of praesūmptiōsus, from praesūmptiō, presumption; see presumption.
(comparative more presumptuous, superlative most presumptuous)