The term 'EXTREMELY LUXURIOUS' can be summarized by the crossword solution of POSH, which is a four-letter word meaning stylish and fashionable in a way that is associated with wealth. It is often used to describe expensive and high-end items, such as clothing, jewelry, and cars. POSH is also used to describe luxurious places, such as hotels, restaurants, and resorts. In short, POSH is a perfect way to describe something that is extremely luxurious.