A feeling or emotion usually mistaken for envy. Jealousy is kind of similar to envy but Jealousy is more inclined to the 'romantic' aspect and Envy is for material possessions.
You are jealous over romantic things others have that you don't; or that may be taken away from you (even by a split second).
Leah had jealousy over that female slutbag who just took a photo of her with Leah's boyfriend.
A red mark on your (most preferably) skin that was formed after someone sucked your blood through your skin.
They say it's a mark of love (or lust, whichever you prefer) and mostly, possessive people do this to their (most preferably) partners in love (or lust).
Luke just placed a hickey on Leah after they had sex.