A pejorative term that is sometimes applicable, sometimes not. It is applicable when applied to some atheists who generally, actually think or maintain that gods do not exists, but posit a "lack of belief" in order to avoid properly discharging their burden of justification. It is not applicable when applied to some atheists who actually do not maintain the belief that gods don't exists. In this case they actually just "lack" the belief, and the pejorative shouldn't be used in a productive conversation.