thesauric collision 

N. Describes the fairly common occurrence amongst literate types, in which two synonymous or near-synonymous words are spoken somewhat atop each other, resulting in the creation of such phrases as "dramastic", "grood," and "for suretain." While these phrases have been used intentionally, true thesauric collisions only result from accidental construction of such phrases.

While Leeroy was at the cocktail party, he accidentally subjected the words "sweet" and "nice" to a thesauric collision, and thus told the Swedish ambassador to the UN that his expensive new martini glass was "swice."

thesauric collision by TerraForce October 22, 2006