Exploring the origin of “effrontery” reveals not only its linguistic evolution but also how it has become a powerful descriptor for audacious behavior in modern times. The earliest known use of the noun effrontery is in the early 1700s. OED's earliest evidence for effrontery is from 1715, in the writing of Myles Davies, bibliographer. Effrontery (noun) refers to behavior that is audacious, shameless, or presumptuous. It implies a boldness that is often regarded as disrespectful or rude, crossing social boundaries in a way that can provoke shock or offense. Over time, the meaning of "effrontery" evolved to include not only shamelessness but also a sense of arrogance and boldness. It is often used to describe behavior that is deliberately provocative or disrespectful, or that shows a lack of regard for social norms. Effrontery definition: Brazen boldness; presumptuousness.