The Collaborative International Dictionary of English v.0.48:

Decorate \Dec"o*rate\ (d[e^]k"[-o]*r[=a]t), v. t. [imp. & p. p.
   Decorated (d[e^]k"[-o]*r[=a]`t[e^]d); p. pr. & vb. n.
   Decorating (d[e^]k"[-o]*r[=a]`t[i^]ng).] [L. decoratus, p.
   p. of decorare, fr. decus ornament; akin to decere to be
   becoming. See Decent.]
   To deck with that which is becoming, ornamental, or honorary;
   to adorn; to beautify; to embellish; as, to decorate the
   person; to decorate an edifice; to decorate a lawn with
   flowers; to decorate the mind with moral beauties; to
   decorate a hero with honors.
   [1913 Webster]

         Her fat neck was ornamented with jewels, rich bracelets
         decorated her arms.                      --Thackeray.

   Syn: To adorn; embellish; ornament; beautify; grace. See
        Adorn.
        [1913 Webster]

   Decorated style (Arch.), a name given by some writers to
      the perfected English Gothic architecture; it may be
      considered as having flourished from about a. d. 1300 to
      a. d. 1375.
      [1913 Webster]

WordNet (r) 3.0 (2006):

decorate
    v 1: make more attractive by adding ornament, colour, etc.;
         "Decorate the room for the party"; "beautify yourself for
         the special day" [syn: decorate, adorn, grace,
         ornament, embellish, beautify]
    2: be beautiful to look at; "Flowers adorned the tables
       everywhere" [syn: deck, adorn, decorate, grace,
       embellish, beautify]
    3: award a mark of honor, such as a medal, to; "He was decorated
       for his services in the military"
    4: provide with decoration; "dress the windows" [syn: dress,
       decorate]

Moby Thesaurus II by Grady Ward, 1.0:

107 Moby Thesaurus words for "decorate":
   accouter, add, adjoin, adorn, affix, agglutinate, annex, append,
   appoint, array, attach, beautify, become one, bedeck, bedizen,
   blazon, burden, caparison, cite, color, complicate, conjoin,
   convolute, crown, crown with laurel, dandify, deck, deck out,
   dizen, do honor, doll up, dress, dress up, elaborate, embellish,
   emblazon, embroider, encumber, enrich, equip, festoon, fig out,
   fix up, flourish, furbish, furnish, garnish, gild, glamorize,
   glue on, grace, gussy up, hitch on, honor, infix, involve,
   join with, load with ornament, ornament, overcharge, overlay,
   overload, paint, paste on, pay regard to, pay tribute, plus,
   postfix, praise, prank, prank up, preen, prefix, prettify,
   pretty up, primp, primp up, prink, prink up, put with, redecorate,
   redo, refurbish, render honor to, renovate, restore, saddle with,
   set off, set out, slap on, smarten, smarten up, spruce up, subjoin,
   suffix, superadd, superpose, tack on, tag, tag on, titivate,
   trick out, trick up, trim, unite with, varnish, wallpaper