What does adult tweens mean?

adult tweens meaning in Urban Dictionary

teenagers involving the many years of 18 and 21 which have person responsibility, although not adult condition. Example: are drafted, can be incarcerated, can enter into agreement, no further at the mercy of parental control; but, cannot acknowledge people self to a hospital with co-consent of somebody 21 or older, cannot eat liquor anyway or be in a place designated over 21 just.