Easton's Bible Dictionary

(Judges 3:15; 20:16), one unable to use the right hand skilfully, and who therefore uses the left; and also one who uses the left as well as the right, ambidexter. Such a condition of the hands is due to physical causes. This quality was common apparently in the tribe of Benjamin.

Noah Webster's New International Dictionary of the English Language

1. (a.) Having the left hand or arm stronger and more dexterous than the right; using the left hand and arm with more dexterity than the right.

2. (a.) Clumsy; awkward; unlucky; insincere; sinister; malicious; as, a left-handed compliment.

3. (a.) Having a direction contrary to that of the hands of a watch when seen in front; -- said of a twist, a rotary motion, etc., looked at from a given direction.