1) An individual who secretely watches another individual from afar, observing and analyzing for their own benifts/motives.
2) Fiend. Someone who will gather information about another person using clandestine and detective-like actions,and will use it to approach them as a friend/ to attempt to enage in sexual or cuffing-type situations.
4)A thirsty individual.
"Yo he read the sign-in roster to find out my last name to request me on facebook! What kind of lurky ish is that?!"