Urban Dictionary OOTNnighttime outfit meaning is a term used to represent an attire that is worn during the night or for special occasions. represents love, emotion, and romance. Therefore, an ootn showcases a trendy and captivating attire that reflects one's affection for clothing and enjoys the evening vibe. Wearing an ootn can enhance your confidence, make an impression, and exude sophistication and charm. No matter it's an glamorous dress or an chic suit, the ootn ensures that you stand out and leave a lasting impression at any evening event.