You know how some people keep talking, on and on and on, and you're so tired of listening to them that you almost feel a little sick? That's an example of speaking ad nauseam: to a sickening extent. Usually, this term is used for things and actions that have worn out their welcome, like a cliché that's repeated ad nauseam. If you're sick of hearing or seeing something, it's happening ad nauseam: too much.