Middle English noun denoting an incorrigible, dogmatic old pedant . Taken from the Latin sumpsimus, a word which was incorrectly copied and read for years in mass by an illiterate fifteenth-century English preacher. Upon being shown his error, the obstinate clergyman reportedly replied, "I will not change my old mumpsimus for your new sumpsimus." This attitude was often ridiculed by French writer Michael Monstaigne, who elegantly wrote of a common human blind spot, "I never met a man who thought his thinking was faulty."