Merriam-Webster Collegiate Dictionary - pyrrhic

 adjective  Etymology: Pyrrhus, king of Epirus who sustained heavy losses in defeating the Romans  Date: 1885 achieved at excessive cost a ~ victory; also costly to the point of negating or outweighing expected benefits a great but ~ act of ingenuity PYRRHIC  noun  Etymology: Latin ~hius, from Greek (pous) ~hios, from ~he, a kind of dance  Date: 1626 a metrical foot consisting of two short or unaccented syllables