A favorite is the team or individual expected to win a particular event. For example, the Kansas City Chiefs are a -7 point favorite over the Denver Broncos, which means the Chiefs are expected to win by seven points.
A favorite can be bet on the moneyline or spread. In the above game, the Chiefs could be a -210 favorite to win the game outright. While a moneyline bet on a favorite is easier to win, it also results in less money won as opposed to a spread bet, which requires the favorite to win by a set number of points. Spread bets such as -7 can have odds ranging from +110 to -110 or even +120 or -120, depending on the sportsbook.