To remain concealed to ambush or observe

• To lie in wait, hidden

To stay unnoticed while hanging around a place

• To move stealthily, avoiding attention

To read online discussions without posting

• To be present in a forum without participating

To saddle someone with an unwanted task or duty

• Slang, chiefly Aus/NZ

The act or instance of lurking

• A period of staying hidden or watching secretly

A swindle or racket

• Slang, chiefly Aus/NZ