For example, Q-Q-K-3-2 would win (because its K kicker outranks the 10), but Q-Q-10-4-3 would lose (because its 4 is outranked by the 5). But the kickers can be used to break ties between other hands that also have a pair of queens. This hand would defeat any hand with no pair, or with a lower-ranking pair, and lose to any higher-ranking hand. For example, the hand Q-Q-10-5-2 is ranked as a pair of queens.
A kicker, also called a side card, is a card in a poker hand that does not itself take part in determining the rank of the hand, but that may be used to break ties between hands of the same rank.