Focused Fighting (3.5e Trait)
From D&D Wiki
You prefer one-on-one combat.
Benefit: When you make a melee or ranged attack, if neither you nor your target are in a square threatened by another creature, you gain a +1 bonus to your attack and damage rolls.
Drawback: If another creature is adjacent to you or or target, you suffer a -2 penalty to the attack roll.