The Collaborative International Dictionary of English v.0.48:
Presumptuousness \Pre*sump"tu*ous*ness\, n. The quality or state of being presumptuous. [1913 Webster]WordNet (r) 3.0 (2006):
presumptuousness n 1: audacious (even arrogant) behavior that you have no right to; "he despised them for their presumptuousness" [syn: presumption, presumptuousness, effrontery, assumption]