swan dive 
North American
noun
A swallow dive.Chessa did a perfect swan dive off the diving board into rippling water below her....
- In Tom's World, it's always better to try a swan dive and deliver a colossal belly flop than to step timidly off the board while holding your nose.
- To do the Mountain Pose with Prayer Hands, inhale as you reverse your swan dive, lifting your hands all the way up over your head.
verb [no object] (swan-dive)
Perform a swan dive: figurative once again the singer has swan-dived into strange waters...
- Were it within Blair's gift to serve up the fall of western civilisation on a plate, I might now be debating which bridge I'd prefer to swan-dive off, Blackfriars or Hammersmith.
- It's greatest effect was on the acquaintance who was there to watch over and make sure I didn't swan-dive into the fire.
- You stand on the top, take a photograph of Manhattan, spread out below you, then swan-dive into midair.