When combined, 生意 (shēngyì) literally means “life's idea” or “generating meaning,” which beautifully encapsulates the concept of “business” or “trade.” 兴隆 (xīnglóng) is a powerful compound word meaning “to prosper and be abundant.” Together, 生意兴隆 (shēngyì xīnglóng) creates a complete and vivid picture: “May your business [生意] flourish and be abundant [兴隆].”
The term is almost always used in a positive and formal or semi-formal context. It is not used sarcastically.