[uhn-uh-mer-i-kuh
n] 
| not American; not characteristic of or proper to the U.S.; foreign or opposed to the characters, values, standards, goals, etc., of the U.S. |
A term used, primarily by extreme conservatives, to attack principles or practices considered to be at odds with the values of most Americans. Many object to the use of the term on the grounds that it is vague, shortsighted, and intolerant.
Note: The House of Representatives maintained a Committee on Un-American Activities (HUAC) for several years. It was especially known for investigation of alleged communists. (See Alger Hiss.)