The Collaborative International Dictionary of English v.0.48:

Immure \Im*mure"\, v. t. [imp. & p. p. Immured; p. pr. & vb.
   n. Immuring.] [Pref. im- in + mure: cf. F. emmurer.]
   1. To wall around; to surround with walls. [Obs.] --Sandys.
      [1913 Webster]

   2. To inclose whithin walls, or as within walls; hence, to
      shut up; to imprison; to incarcerate.
      [1913 Webster]

            Those tender babes
            Whom envy hath immured within your walls. --Shak.
      [1913 Webster]

            This huge convex of fire,
            Outrageous to devour, immures us round. --Milton.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Immure \Im*mure"\, n.
   A wall; an inclosure. [Obs.] --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

immure
    v 1: lock up or confine, in or as in a jail; "The suspects were
         imprisoned without trial"; "the murderer was incarcerated
         for the rest of his life" [syn: imprison, incarcerate,
         lag, immure, put behind bars, jail, jug, gaol,
         put away, remand]

Moby Thesaurus II by Grady Ward, 1.0:

71 Moby Thesaurus words for "immure":
   bastille, bolt in, bottle up, box in, box up, cabin, cage, casket,
   cast in prison, check, clap in jail, clap up, cloister, closet,
   coffin, confine, constrain, coop, coop in, coop up, cork up,
   corral, cramp, crib, detain, encage, encase, enclose, entomb,
   fence, fence in, gaol, hedge, hem, hem in, hold, hold captive,
   hold in captivity, hold in custody, hold in restraint,
   hold prisoner, impound, imprison, incarcerate, inhibit, intern,
   jail, jug, keep in, keep in custody, keep in detention, lock in,
   lock up, mew, mew up, pen, pen up, pound, prison, quod, rail in,
   restrain, restrict, seal up, shackle, shut in, shut up, straiten,
   throw into jail, wall, wall in