Courtesy, or 여의 in Korean Hangul (pronounced ye-wee), refers to showing courtesy to all others in the dojang (training area or school) as well as people you may meet outside of formal Taekwondo training. Included in this tenet is observing correct etiquette and manners at all times.
Integrity, or 염치 in Korean Hangul (pronounced yom-chee), includes not only the general definition of integrity where one is not only able to determine the difference between right and wrong but also being able to stand up for what is ethically correct. Being honest and having strong moral principles is paramount and working hard to be beyond corruption are important aspects of the tenet of integrity.
Perseverance, or 인냬 in Korean Hangul (pronounced een-nay), simply refers to the willingness of the Taekwondo student to continue to struggle against all odds to reach their goal. This applies to their Taekwondo training as well as other aspects of their lives.
Self control, or 극기 in Korean Hangul (pronounced gook-gee), means to have control over your thoughts as well as your actions. Maintaining a pure mind as well as a pure body by keeping your emotions in check, particularly in difficult or trying circumstances.
Indomitable spirit, or 백절불굴 in Korean Hangul (pronounced beckjool boolgool), is difficult to define but generally refers to having the courage to stand up for your beliefs and to stay strong in those beliefs and convictions no matter what the odds against you may be. It also refers to consistently exhibiting a full 100% effort in all that you do inside the dojang (training area) and in life.