With the abilities in Pokémon X & Y, although there are new ones, there are also several abilities which have been altered slightly. These abilities are listed as follows:

Name Effect Alteration
Drizzle The Pokémon makes it rain when it enters a battle. Weather effect lasts 5 turns now, rather than permanent.
Drought Turns the sunlight harsh when the Pokémon enters a battle. Weather effect lasts 5 turns now, rather than permanent.
Infiltrator The protections and stat boosts caused by the moves Reflect, Light Screen and Safeguard by the opponent are ignored. Now allows the Pokémon to hit through a substitute
Keen Eye Opponent cannot lower this Pokémon’s accuracy. Now also ignores evasion boosts of the opponent
Oblivious Prevents the Pokémon from becoming infatuated. Now also protects against Taunt
Overcoat Protects the Pokémon from things like sand, hail, and powder. Also protects Pokémon from Powder moves such as Sleep Power, Poison Powder etc.
Sand Stream The Pokémon summons a sandstorm in battle. Weather effect lasts 5 turns now, rather than permanent.
Snow Warning The Pokémon summons a hailstorm when it enters a battle. Weather effect lasts 5 turns now, rather than permanent.