Off-hand

From NWNWiki

Off-hand refers to your left hand in Neverwinter Nights as all characters are assumed to be right handed.

When dual-wielding, the off-hand weapon gains a 50% damage bonus (rounded down) from the strength modifier (as opposed to 100% for the primary hand or 150% when using a two-handed weapon).

For information about wielding a weapon in the off-hand, see dual-wield.