Urban Dictionary OOTNoutfit of the night heart importance is a phrase used to depict an ensemble that is put on during the night or for special occasions. symbolizes love, passion, and romance. Therefore, an ootn showcases a fashionable and alluring attire that reflects the affection for fashion and enjoys the evening vibe. Wearing an ootn can boost your confidence, make an impression, and exude elegance and charisma. Regardless of it's a glamorous dress or an chic suit, the ootn will ensure that you stand out and leave a lasting impression at any night event.