What is the opposite of "thrive"?

The term "thrive" refers to the act of growing well or developing vigorously, often in a positive context. Therefore, its opposite would signify a decrease, deterioration, or failing to succeed. The word "decline" encapsulates this concept effectively, as it denotes a reduction in quality, quantity, or strength. When something declines, it moves away from a state of thriving towards one of worsening conditions, making it the correct opposite. In contrast, the other options like "to grow," "to prosper," and "to flourish" all suggest positive growth or improvement, which aligns more with thriving rather than its opposite.