An overly proper person is often referred to as a PRIG or a PRUDE. A PRIG is someone who is excessively concerned with propriety and etiquette, often to the point of being annoying or irritating. A PRUDE is someone who is excessively modest or proper, often to the point of being overly conservative or judgmental. Both terms are used to describe someone who is overly concerned with following rules and conventions, often to the point of being overly strict or rigid.