An attack is a numerical value that is printed on Creature cards. It indicates the Strength of a card in Dragoborne.

While Attacking

While attacking, the attack value of a card comes into play. When a player decides to attack, the attack value of attacking card, and the endurance value of the defending card is compared. If the attack value is greater than the endurance value, the attack hits successfully.

Naturally, the card with greater attack value is considered good for offense.