also antiamerican, 1773, in reference to British parliamentary policies, from anti- + American. As a noun by 1788. Related: Anti-Americanism "opposition to what is distinctly American" (1844).

The term "anti-American" is a loose one, and loosely employed. My own working definition of it, admittedly a slack one also, is that a person is anti-American if he or she is consistently contemptuous of American culture and furthermore supports any opponent of U.S. policy, whoever this may be. [Christopher Hitchens, review of "The Life of Graham Greene, Vol. II," The Atlantic, March 2005]

"American quality, origination, or nature," 1860, from American (adj.) + -ness.

Our legislator took to Congress several securities against erroneous action, several securities of largeness, liberality, American-ness, if I may be suffered thus to coin a word. [Robert B. Warden, "Life and Character of Stephen Arnold Douglas," Columbus, 1860]

"not characteristic of American principles or methods, foreign to U.S. customs," 1818, from un- (1) "not" + American (adj.).

Everything is un-American that tends either to government by a plutocracy or government by a mob. [Theodore Roosevelt, 1917]