Limerence is primarily a state of romantic attraction with intense feelings of erotic love and attraction towards a person who is often otherwise occupied by an love connection and often unsuitably older.
First loves, puppy loves and crushes' are other terminologies because most limerence reflects chronological development.
Limerent experiences are usually impossible because of practical issues ( local morality and family values, age disparity, authority issues, and propinquity) so the lime'rent person experiences a powerful mixture of elation and despair which can last for a long period of time.
There is often a transference component involved.
Successfully resolved limerencs laads to a more grounded capacity in choosing suitable love-objects.