rapidest

adjective
  1. 1

    Very swift or quick.

    โ€œa rapid streamโ€

  2. 2

    Steep, changing altitude quickly. (of a slope)

  3. 3

    Needing only a brief exposure time. (of a lens, plate, film, etc.)

  4. 4

    Violent, severe.

  5. 5

    Happy.

Source: https://en.wiktionary.org/wiki/rapid, https://en.wiktionary.org/wiki/rapidest