'ILY' stands for 'I love you' — used affectionately in texts to family and close friends as well as romantic partners. The casual abbreviation makes the heavy phrase 'I love you' easier to send. If your teen signs off with 'ily' to a friend, they are expressing affection in a friendly, low-stakes way. Harmless and warm. Variations: 'ilysm' (= I love you so much), 'ily2' (= I love you too).