Urban Dictionary OOTNnighttime outfit heart meaning is a phrase used to depict an attire that is worn in the evening or for special occasions. Heart symbolizes love, emotion, and affection. Therefore, an ootn showcases a fashionable and captivating attire that reflects the affection for clothing and enjoys the evening vibe. Sporting an ootn can boost one's confidence, make a statement, and display elegance and charisma. Whether it's a glamorous dress or an chic suit, the ootn guarantees that you stand out and leave a lasting impression at any night event.