Synonyms for Lurk (same or very similar meaning)
WordNet sense 1 (lie in wait, lie in ambush, behave in a sneaky and secretive manner):
skulkWordNet sense 2 (be about):
lallygag, linger, loaf, loiter, lollygag, lounge, tarry, footle, tarry, hang around, mess about, mill about, mill aroundWordNet sense 3 (wait in hiding to attack):
ambuscade, ambush, bushwhack, scupper, waylay, lie in waitFrom the ODE community, based on WordNetadd/edit