The most common and most likely answer to this crossword clue is the 5 letter word GRAND
I've seen this crossword clue in Independent
G
R
A
N
D
Buddy explains!

The straight part
We know that "Luxurious" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case luxurious = grand.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does GRAND mean?
GRAND noun- (plural "grand") A thousand of some unit of currency, such as dollars or pounds. (Compare G.)
- (plural "grands") A grand piano
- Of a large size or extent; great.
- Great in size, and fine or imposing in appearance or impression; illustrious, dignified, magnificent.
- Having higher rank or more dignity, size, or importance than other persons or things of the same name.
- (usually in compound forms) Standing in the second or some more remote degree of parentage or descent.
- Fine; lovely.
- Containing all the parts proper to a given form of composition.
- A grandparent or grandchild.