RINO
n. A member of the Republican party who is viewed as being too liberal.
Also Seen As
Etymology
Examples
2004
After all, Moore said, "I think if you're a Republican in 2004 you've got to stand for a few things. You've got to be for school choice, and you've got to be for cutting taxes, and you've got to be for smaller government. Otherwise, what are Republicans good for? That's why we keep saying [Arlen] Specter's a rino—a Republican in name only—and let's replace him with a real Republican."
—Philip Gourevitch, “Fight on the Right,” The New Yorker, April 12, 2004
2004
Because it is a Republican primary, these RINOs cannot come out and proclaim their political colors. They must disguise their views the way a real rhino might hide in the tall grass from a hunter

Hence, every liberal/moderate Republican running March 2 champions his and her "conservative'' views, especially on the safe tax, fiscal and regulatory issues.
—Steven Greenhut, “RINOplasty,” The Orange County Register (California), February 22, 2004
1992 (earliest)
Bill Clinton would have been proud of what was happening on the third-floor Senate corner at the State House this week.

The Republicans were moving out and the Democrats and "RINOs" (Republicans In Name Only) were moving in.
—John DiStaso, “Merrill Taps Scamman, Strome and a Thomson,” The Union Leader (Manchester, NH), December 31, 1992
Notes
This term is an acronym based on the phrase Republican in name only, and it's an epithet likely to be hurled quite often in the coming U.S. election season. And, yes, the opposite creature also exists: the DINO (1994) is a Democrat in name only, meaning a member of the Democratic party who is viewed as being too conservative.