The Collaborative International Dictionary of English v.0.48:

Desolate \Des"o*late\, v. t. [imp. & p. p. Desolated; p. pr. &
   vb. n. Desolating.]
   1. To make desolate; to leave alone; to deprive of
      inhabitants; as, the earth was nearly desolated by the
      flood.
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   2. To lay waste; to ruin; to ravage; as, a fire desolates a
      city.
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            Constructed in the very heart of a desolating war.
                                                  --Sparks.
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The Collaborative International Dictionary of English v.0.48:

Desolate \Des"o*late\, a. [L. desolatus, p. p. of desolare to
   leave alone, forsake; de- + solare to make lonely, solus
   alone. See Sole, a.]
   1. Destitute or deprived of inhabitants; deserted;
      uninhabited; hence, gloomy; as, a desolate isle; a
      desolate wilderness; a desolate house.
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            I will make Jerusalem . . . a den of dragons, and I
            will make the cities of Judah desolate, without an
            inhabitant.                           --Jer. ix. 11.
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            And the silvery marish flowers that throng
            The desolate creeks and pools among.  --Tennyson.
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   2. Laid waste; in a ruinous condition; neglected; destroyed;
      as, desolate altars.
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   3. Left alone; forsaken; lonely; comfortless.
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            Have mercy upon, for I am desolate.   --Ps. xxv. 16.
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            Voice of the poor and desolate.       --Keble.
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   4. Lost to shame; dissolute. [Obs.] --Chaucer.
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   5. Destitute of; lacking in. [Obs.]
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            I were right now of tales desolate.   --Chaucer.

   Syn: Desert; uninhabited; lonely; waste.
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WordNet (r) 3.0 (2006):

desolate
    adj 1: providing no shelter or sustenance; "bare rocky hills";
           "barren lands"; "the bleak treeless regions of the high
           Andes"; "the desolate surface of the moon"; "a stark
           landscape" [syn: bare, barren, bleak, desolate,
           stark]
    2: crushed by grief; "depressed and desolate of soul"; "a low
       desolate wail"
    v 1: leave someone who needs or counts on you; leave in the
         lurch; "The mother deserted her children" [syn: abandon,
         forsake, desolate, desert]
    2: reduce in population; "The epidemic depopulated the
       countryside" [syn: depopulate, desolate]
    3: cause extensive destruction or ruin utterly; "The enemy lay
       waste to the countryside after the invasion" [syn: lay waste
       to, waste, devastate, desolate, ravage, scourge]