i swear on me nans grave - A lazy excuse used by someone who doesn’t want to admit they

A lazy excuse used by someone who doesn’t want to admit they’re lying, and probably doesn’t care about their nan either.

I swear on me nans grave I didn’t eat the last biscuit.

I swear on me nans grave I didn’t copy your answers.

I swear on me nans grave I didn’t tell the teacher about your bad behavior.