Is it ensure, insure, or assure?
"erring in purpose or action," 1650s, past participle adjective from misguide (v.). Earlier, "ill-behaved" (late 15c.). Related: Misguidedly; misguidedness.
late 14c., "to go astray;" see mis- (1) + guide (v.). Transitive sense of "to guide in the wrong direction" is first attested c.1500. Related: Misguided; misguiding.