catachresis \kat-uh-KREE-sis\, noun:
Misuse or strained use of words, as in a mixed metaphor, occurring either in error or for rhetorical effect. Catachresis is derived from the Greek root chrêsis which meant "to use." The prefix cata- means "down, back, against." The word katachrêsthai meant "to misuse" in Greek.