un-American 
adjective
1Not in accordance with American characteristics: such un-American concepts as subsidized medicine and free education...
- When the tumult died and the gold dust settled, in continuance of a trend that feels at once deeply American and deeply un-American, loners, outsiders, misfits, deviants and freaks ruled the day at the 2003 Sundance film festival.
- The problem is, American politics are un-American.
- By doing so, these films attempted to redraw the line between American and un-American not along racial lines, as it was then being framed within the public debate, but rather along the lines of personal value judgments.
1.1US, chiefly historical Contrary to the interests of the US and therefore treasonable: some American artists were denounced as un-American...
- It goes against the values of the Constitution, the foundation on which our country was built, and is therefore un-American.
- There was nothing aberrant about this, nothing outre or un-American; quite the contrary.
- Dissent is un-American and therefore justifiably punished by a fine.
Derivatives
un-Americanism
- Nowhere has your un-Americanism been more poignantly explained and demonstrated than on the New York Times opinion pages over the last two days.
- In light of the Palmer Raids and the growing belief that ‘outsiders’ were threatening American institutions, the steel strike became a symbol of un-Americanism, not of a legitimate battle between labor and capital.
- The drama darkens, of course, John Rankin and J. Parnell Thomas ride into the golden shtetl to accuse them, with their swimming pools and yachts and second, younger, gentile trophy wives, of un-Americanism.