IPA: /lʌɡˈʒʊəriəsnəs/
KK: /lʌkˈʒʊəriəsnəs/
The quality of being very comfortable, elegant, and expensive, often involving great wealth or indulgence.
The luxuriousness of the hotel made our stay unforgettable.
Luxuriousness → It is formed from "luxurious" (from Latin "luxuriosus", meaning extravagant or indulgent) and the suffix "-ness" (meaning the state or quality of). The word "luxuriousness" refers to the state of being luxurious or characterized by luxury.
Think of 'luxurious' which means extravagant or indulgent, and remember that 'luxuriousness' describes the state of being indulgent.