One Hander

One Hander (called Unidextrous in TORN) is a Fallout, Fallout 2, Fallout Tactics, Van Buren, Lionheart and TORN trait.

Fallout, Fallout 2, Fallout Tactics
This trait gives a -40% chance to hit with two-handed weapons, but +20% to hit with weapons that only require one hand.

Affected weapons are Unarmed, Melee, Small Guns and Energy Weapons pistols, and Throwing weapons.

J.E. Sawyer's Fallout RPG
This trait provides a +2 chance to hit with one-handed weapons, but -2 to hit with two-handed weapons.

Lionheart
You suffer an initial -10 to Two-Handed Weapon skill and -10 to Ranged Weapon skill but obtain a +10 to One-Handed Weapon Skill.

TORN
The character is +20% to-hit with one-handed weapons, but -40% to-hit with two-handed weapons and suffers an additional -40% to-hit penalty when dual-wielding.