Velvet RiverFold
To give up your hand and any claim to the pot, discarding your cards.
Folding costs nothing more than what you have already put in. Good players fold far more often than beginners expect: around three quarters of starting hands preflop at a full table.
You can fold whenever it is your turn to act. Folding when you could check for free is a beginner error, and in live tournaments it is frowned upon.