豪华 (háo huá) describes something luxurious and high-end, like a hotel or car — it's the neutral, everyday word for luxury. 奢侈 (shē chǐ) adds a sense of extravagance or waste, often negative; 华丽 (huá lì) focuses on visual splendor and decoration; 高贵 (gāo guì) refers to noble birth or dignified elegance.