Limerence, as posited by psychologist Dorothy Tennov, is an attempt at a scientific study into the nature of romantic love. The meaning of the word, which was coined by Tennov in 1977, is an involuntary cognitive and emotional state in which a person feels an intense romantic desire for another person, the limerent object.
It is characterized by intrusive thinking and pronounced sensitivity to external events that reflect the disposition of the limerent object towards the individual. It can be experienced as intense joy or as extreme despair, depending on whether the feelings are reciprocated. Unlike English, many other languages have traditional terms to denote limerence, like in German Verliebtheit or Russian влюблённость (vlyublyonnost); both expressions may roughly be translated to “fallen-in-love-ness.”