The term 'relative of muttonchops' can be solved by the crossword solution 'Burnsides' (9 letters). The term 'Burnsides' refers to a style of facial hair, which is a variation of muttonchops. It is named after American Civil War General Ambrose Burnside, who was known for his distinctive facial hair. The style consists of sideburns that are grown long and bushy, extending down the sides of the face and meeting with a full mustache.