m. 1. unawares, unprepared, by surprise or off one's guard. This phrase comes from the game of baseball where a batter (batsman), after havinghit a ball, attempts to run to one or more bases, ultimately returning to the place from which he hit the ball in order to score. Once having made it to a base, if he incautiously steps off it while waiting for the opportunity to run again, the opposing team may tag him (catch him off base) with the ball and put him out of play. 2. inaccurate or wrong in some way; mistaken. 3. out of the ordinary or unusual.