The Collaborative International Dictionary of English v.0.48:

Standstill \Stand"still`\ (-st[i^]l`), n.
   A standing without moving forward or backward; a stop; a
   state of rest.
   [1913 Webster]

WordNet (r) 3.0 (2006):

standstill
    n 1: a situation in which no progress can be made or no
         advancement is possible; "reached an impasse on the
         negotiations" [syn: deadlock, dead end, impasse,
         stalemate, standstill]
    2: an interruption of normal activity [syn: stand,
       standstill, tie-up]

Moby Thesaurus II by Grady Ward, 1.0:

47 Moby Thesaurus words for "standstill":
   arrest, bell, blind alley, box, cessation, check, checkmate,
   corner, cul-de-sac, cutoff, dead end, dead set, dead stand,
   dead stop, dead-end street, deadlock, dying down, ebb, ebbing, end,
   endgame, ending, extremity, final whistle, full stop,
   grinding halt, gun, halt, hole, impasse, lock, lockout, pause,
   sit-down strike, stalemate, stand, standoff, stay, stillstand,
   stop, stoppage, strike, subsidence, walkout, wane, waning,
   work stoppage