(nō′nuth′ing) noun
An uneducated or ignorant person; an ignoramus.

(nō′nuth′ing) noun
A member of a party in U. S. politics (1853–56), which aimed at excluding foreign–born persons from the government, and at making it difficult for them to become citizens: so called because, in its original form as a secret society, its members professed to “know nothing” about it when questioned.
—Know′–noth′ing·ism noun