1.Lit. [of a runner in baseball] not having a foot touching the base. (*Typically: be ~; get ~.) The runner was off base but the first baseman didn't tag him out.
2.Fig. unrealistic; inexact; wrong. *Typically: be ~; get ~.) I'm afraid you're off base when you state that this problem will take care of itself.You're way off base if you think I was to blame!
Wrong, relying on a mistaken premise, as in His description of the accounting system was totally off base. This metaphoric term originated in baseball, where a runner who steps off a base can be put out. [c. 1940]