Unaware is a Pokémon ability introduced in the fourth generation. It allows the user to ignore stat changes.
When a Pokémon with this ability is targeted by a move or targets another with a move, it ignore all stat changes of the opposing Pokémon. This means when the Pokémon attacks a Pokémon, any evasion boosts are ignored when calculating if it will hit and it ignores the defense or special defense boosts of the defending Pokémon in damage calculation. It also means when a Pokémon attacks, their accuracy boost are ignored in determining if it will hit and their attack or special attack boosts are ignored in damage calculation