The act of lurking.

(obsolete) A swindle.

To remain concealed in order to ambush.

To remain unobserved.

To hang out or wait around a location, preferably without drawing attention to oneself.

(Internet slang) To read an Internet forum without posting comments or making one's presence apparent.

(UK, naval slang, transitive) To saddle (a person) with an undesirable task or duty.