Boldly impudent; saucily forward in a way that presumes permission it has not been given. Where rudeness can be blunt, malapert has a pert cheekiness to it, insolence with a smirk.

From Old French mal apert “ill-suited; ill-bred,” literally “badly open” (mal “badly” + apert “open, frank”). What begins as “too open” becomes, in social life, “too bold.”