WordNet (r) 3.0 (2006):

shut off
    v 1: stem the flow of; "shut off the gas when you leave for a
         vacation" [syn: shut off, close off]
    2: isolate or separate; "She was shut off from the friends"
       [syn: shut off, close off]
    3: block off the passage through; "We shut off the valve" [syn:
       shut off, block off, close off]

Moby Thesaurus II by Grady Ward, 1.0:

114 Moby Thesaurus words for "shut off":
   abrupt, alienate, alienated, apart, bar, barricade, block,
   block out, block up, blockade, bolt, cast off, cast out, chock,
   choke, choke off, close, close off, close tight, close up,
   constrict, crowd, cut, cut adrift, cut off, cut out, debar, delete,
   depart, detached, disarticulate, disarticulated, disconnect,
   disconnected, disengage, disengaged, disjoin, disjoined, disjoint,
   disjointed, disjunct, dislocated, dispersed, dissociate, disunite,
   disunited, divide, divided, divorce, divorced, dog, eject,
   estrange, estranged, expel, in a backwater, insular, isolate,
   isolated, jam, kill, leave, lock, obstruct, occlude,
   out-of-the-way, out-of-the-world, pack, part, pull away, pull back,
   pull out, quarantined, remote, removed, retired, scattered,
   secluded, segregate, segregated, separate, separated, sequester,
   sequestered, set apart, set aside, shroud, shut, shut down,
   shut out, shut tight, split, squeeze, squeeze shut, stand aloof,
   stand apart, stand aside, step aside, stifle, stop up, strangle,
   strangulate, subtract, suffocate, switch off, throw off, throw out,
   turn off, uncouple, unfrequented, unvisited, unyoke, withdraw,
   withdrawn