zhì​de​fēi​yuè

qualitative leap

  1. quality
    quality; character; the fundamental nature of something or the standard of excellence of a product or work
  2. de particle
    [possessive/attributive]
    Connects a describing word or phrase to the noun it describes; also used to indicate a possessive relationship.
  3. leap (breakthrough)
    to develop rapidly; a sudden and significant breakthrough or advancement in progress