Fold

betting

Discarding your hand and forfeiting any chance at the pot.

The most underused button at low stakes. Folding to obvious value is more profitable than calling 'just in case'.

See also

All-In
Betting all your remaining chips.
Ante
A forced bet all players must post before each hand.
Barrel
A continuation bet on a later street (double = flop+turn, triple = + river).
Blind
A forced bet posted before the cards are dealt.