The term 'Rules Maven' is often used to describe someone who is an expert in the rules of a particular game or activity. The crossword solutions for this term are 'HOYLE, ' which is a reference to Edmond Hoyle, an English writer who wrote books on the rules of card games and other activities. He is considered to be the authority on the rules of many games and activities, and thus the term 'Rules Maven' is often used to describe someone who is an expert in the rules of a particular game or activity.