forbothered
When someone feigns that they had forgotten a task that they couldn't be bothered to do in the first place.
Dad: "Andrew, did you take the trash downstairs like you said you would".
Andrew "no I forgot"
Dad: "You forgot or you couldn't be bothered"
Andrew: "I forbothered".
Andrew "no I forgot"
Dad: "You forgot or you couldn't be bothered"
Andrew: "I forbothered".