miss by a mile

miss (something) by a mile

Fig. to fail to hit something by a great distance; to land wide of the mark. Ann shot the arrow and missed the target by a mile. "Good grief, you missed by a mile," shouted Sally.
See also: mile, miss

miss by a mile

Fall short, fail by a considerable amount, as in Your guess as to the winner missed by a mile. This expression employs miss in the sense of "fail to hit something aimed at," a usage dating from the late 1400s, and by a mile for a great distance or interval, so used since Shakespeare's day.
See also: mile, miss