WordNet (r) 3.0 (2006):

dress up
    v 1: put on special clothes to appear particularly appealing and
         attractive; "She never dresses up, even when she goes to
         the opera"; "The young girls were all fancied up for the
         party" [syn: overdress, dress up, fig out, fig up,
         deck up, gussy up, fancy up, trick up, deck out,
         trick out, prink, attire, get up, rig out, tog
         up, tog out] [ant: dress down, underdress]
    2: make something appear superficially attractive; "The
       researcher tried to dress up the uninteresting data"; "Don't
       try to dress up the unpleasant truth" [syn: dress up,
       window-dress]
    3: put a caparison on; "caparison the horses for the festive
       occasion" [syn: caparison, bard, barde, dress up]
    4: dress in a costume; "We dressed up for Halloween as pumpkins"
       [syn: costume, dress up]
    5: dress in a certain manner; "She dresses in the latest Paris
       fashion"; "he dressed up in a suit and tie" [syn: dress,
       dress up]

Moby Thesaurus II by Grady Ward, 1.0:

90 Moby Thesaurus words for "dress up":
   adorn, apparel, array, attire, beautify, bedeck, bedizen, belie,
   blazon, camouflage, clad, clothe, color, dandify, deck, deck out,
   decorate, disguise, distort, dizen, doll up, dress, embellish,
   emblazon, embroider, enclothe, enrich, falsify, fancy up, fig out,
   fix up, fudge, furbish, garb, garble, garment, garnish, get up,
   gild, gloss, gloss over, grace, gussy up, mask, miscite, miscolor,
   misquote, misreport, misrepresent, misstate, ornament, overdress,
   overstate, paint, pervert, prank, prank up, preen, prettify,
   pretty up, primp, primp up, prink, prink up, rag out, raiment,
   redecorate, redo, refurbish, set off, set out, slant, slick,
   slick up, smarten, smarten up, smug, spiff, spruce up, strain,
   titivate, toggle, trick out, trick up, trim, twist, understate,
   varnish, warp, whitewash