In poker variants with community cards, an underpair is a pair made from only a player's cards that is smaller than any card on the board. Hence, any pair made with the board will beat an underpair.

Example (Texas Hold'em):

Player Flop
A, K, and 10 are all larger than 8, so the pair is an underpair.

Related Topics:

Overpair, Pair, Top Pair, Middle Pair, Bottom Pair