‘虎头蛇尾’ is an idiom that literally means ‘tiger’s head, snake’s tail’. It vividly contrasts the powerful, imposing image of a tiger’s head with the thin, tapering, and seemingly insignificant tail of a snake — symbolizing a strong, energetic, or impressive beginning that collapses into a weak, unconvincing, or disappointing conclusion. The idiom originates from classical Chinese literature and painting criticism, where it was used to describe works that start boldly but lack follow-through or resolution.

This expression is commonly used in both spoken and written Mandarin to critique projects, speeches, performances, or personal efforts that show great initial enthusiasm or capability but fizzle out toward the end. It carries a mildly negative, evaluative tone — implying wasted potential or poor planning — and often appears in feedback, reviews, or casual commentary about unfinished or uneven endeavors.