swan dive

/S W AA1 N D AY1 V/
noun
  1. 1

    A forward dive performed with an arched back, the legs together, starting with arms outstretched when jumping, bringing them over the head when landing.

  2. 2

    A similar movement out of the water.

  3. 3

    A sharp drop, sharp decline

Synonyms

Source: https://en.wiktionary.org/wiki/swan%20dive