Something that is sumptuous is very expensive, grand, and luxurious, often involving a lot of good food or beautiful things.
When something is sumptuous, it is usually very nice and makes people feel happy and special.
Examples:
The king's palace was sumptuous and beautiful.
We had a sumptuous feast with lots of delicious food.
She wore a sumptuous dress to the party.
The hotel room was so sumptuous, it felt like a dream.
The sumptuous banquet had so much food, it could feed an army.
The sumptuous garden was full of colorful flowers and sweet smells.