Main Love Interest.
The (usually primary) character in a work of fiction who is meant to be the true love of the protagonist. This especially applies to genres where there are many possible pairings, the purest example being harem anime/manga.
In the series Love Hina, Naru Narusegawa is the MLI of Keitaro Urashima.
A large romanian teddybear, filled with crack to mislead ones parents.
Me and my friends cut mli open and had a good time.