1Luxury; extravagance — spending or having more than is strictly needed, for comfort or pleasure.
彼は年に一度、贅沢をして高級ホテルに泊まる。
Once a year, he treats himself and stays at a luxury hotel.
新品の時計も買えるが、今は贅沢だと思って我慢している。
I could buy a new watch, but right now I'm holding back because it feels like an extravagance.
『贅沢は敵だ』と言う人もいるが、節度があれば問題ない。
Some people say "luxury is the enemy," but it's fine as long as you keep it in moderation.
2To live extravagantly or indulge oneself, seeking more comfort or pleasure than is strictly needed (usually as 贅沢する).
旅行中はつい贅沢してしまい、予算をオーバーした。
I ended up indulging myself during the trip and went over budget.
たまには贅沢してもいいよ。毎日よく頑張っているんだから。
It's fine to indulge yourself once in a while — you've been working hard every day.
3Lavish; abundant — using something in generous amounts without holding back (usually as 贅沢に).
このケーキは生クリームを贅沢に使っているので濃厚だ。
This cake uses fresh cream lavishly, so it's very rich.
旬の食材を贅沢に盛り付けた寿司が人気だ。
Sushi lavishly topped with seasonal ingredients is popular.
4Excessive — going beyond what is reasonable to demand or expect (often as 贅沢を言う, "to ask for too much").
高品質を求めるのはいいが、この値段でそれは贅沢だ。
It's fine to want high quality, but that's asking too much for this price.
『贅沢を言わないで、今あるもので我慢しなさい』と母に言われた。
My mother told me, "Don't ask for too much — make do with what you have."