Gawain has strength and endurance. Skill at arms. Gawain is ready to fight. Gawain is willing to accept the challenge. Courtesy is partly good manners, partly a set of conventions related to courtly love.
Loyalty is the keystone of the feudal system.
Gawain is loyal to Arthur, to Bercilak, and to his own word. His failure is in loyalty. Gawain's adherence to the knightly ideals is symbolized in his emblem, the Pentangle. The pride of the court is deflated, but Gawain remains admirable, even though he shows human weakness. It developed partly out of the cult of Mary, which elevated women.