lurk v.

"to look dark and menacing," also lour, from Middle English louren, luren "to frown, scowl" (early 13c.), "to lurk" (mid-15c.), from Old English *luran or from its cognates, Middle Low German luren, Middle Dutch loeren "lie in wait." The form perhaps has been assimilated to lower (v.1). Related: Lowered; lowering.

"predicament," 1580s, from Middle English lurch (v.) "to beat in a game of skill (often by a great many points)," mid-14c. (implied in lurching), probably literally "to make a complete victory in lorche," an old game akin to backgammon, with a name of uncertain origin. Perhaps it is related to Middle English lurken, lorken "to lie hidden, lie in ambush" (Middle English Compendium; see lurk), or it may be from Old French lourche, from Middle High German lurz "left," also "wrong" [OED]. The immediate source of the transferred use in leave in the lurch "leave suddenly and unexpectedly in an embarrassing predicament" (1590s) would be cribbage.

"one who keeps out of sight," early 14c., agent noun from lurk (v.). In the internet sense by 1990.