The Collaborative International Dictionary of English v.0.48:

Immerse \Im*merse"\, v. t. [imp. & p. p. Immersed; p. pr. &
   vb. n. Immersing.]
   1. To plunge into anything that surrounds or covers,
      especially into a fluid; to dip; to sink; to bury; to
      immerge.
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            Deep immersed beneath its whirling wave. --J Warton.
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            More than a mile immersed within the wood. --Dryden.
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   2. To baptize by immersion.
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   3. To engage deeply; to engross the attention of; to involve;
      to overhelm.
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            The queen immersed in such a trance.  --Tennyson.
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            It is impossible to have a lively hope in another
            life, and yet be deeply immersed inn the enjoyments
            of this.                              --Atterbury.
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The Collaborative International Dictionary of English v.0.48:

Immersed \Im*mersed"\, p. p. & a.
   1. Deeply plunged into anything, especially a fluid.
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   2. Deeply occupied; engrossed; entangled.
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   3. (Bot.) Growing wholly under water. --Gray.
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Moby Thesaurus II by Grady Ward, 1.0:

86 Moby Thesaurus words for "immersed":
   absorbed, absorbed in, awash, bathed, buried, buried in,
   caught up in, contemplating, contemplative, deep, deluged, devoted,
   devoted to, dipped, drenched, dribbling, dripping, dripping wet,
   drowned, engaged, engrossed, engrossed in, engulfed, enmeshed in,
   entangled in, far-gone, flooded, immersed in, implicated in,
   intent, intent on, inundated, involved, involved in, lost in,
   macerated, meditating, meditative, monomaniacal, monopolized,
   obsessed, occupied, oozing, overflowed, permeated, preoccupied,
   rapt, saturated, seeping, single-minded, soaked, soaking,
   soaking wet, soaky, sodden, soggy, sopping, sopping wet, soppy,
   soused, steeped, studious, studying, subaqueous, submarine,
   submerged, submerged in, submersed, sunken, swamped, swept up,
   taken up with, tied up in, totally absorbed, undersea, underwater,
   waterlogged, watersoaked, weeping, weltering, whelmed, wrapped,
   wrapped in, wrapped up, wrapped up in, wringing wet