a lilly is a wonderful person and a dear friend. it comes from the flower lily because the friendship she holds is just as pure as these beautiful flowers.
A girl that only has had sex with one person and does not want topartake in sex with anyone else much like Lilly in the popular Tv show how i met your mother.
The one friend in the groupconversation in a public setting where when there is silence they continue to talk about something nobody cares about and is completely off topic.