### Clue: This water is so turbulent at first – call in pontoon (5)
### Answer: TWIST 
 ### Explanation: Definition: call in pontoon
  First letters(*at first*) of *This Water Is So Turbulent*.
Defn:  A *call in* the card game of *pontoon*, similar to blackjack, where a player tells the dealer to "twist (me one)", ie. to deal another card, face up, to the player.  The twisting action comes from taking the top card from the deck and flipping it face up.