迅猛 is a compound adjective formed by combining 迅 (xùn), meaning 'swift' or 'rapid', and 猛 (měng), meaning 'fierce', 'powerful', or 'intense'. Together, they describe something that develops, moves, or acts with both extraordinary speed and force — not merely fast, but explosively so. The word carries a strong, dynamic connotation and often implies intensity, urgency, or overwhelming momentum.

It’s commonly used to describe rapid growth, sudden surges, or powerful natural phenomena — especially in contexts involving animals (e.g., predators launching attacks), technological advancement, economic expansion, or natural disasters. While it can modify nouns directly (e.g., 迅猛的发展), it frequently appears in descriptive phrases emphasizing scale and pace. It’s formal and literary in register, rarely used in casual speech, and almost never applied to people’s personal actions unless in metaphorical or journalistic contexts (e.g., a politician’s ‘迅猛崛起’).