WordNet (r) 3.0 (2006):

gussy 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]

Moby Thesaurus II by Grady Ward, 1.0:

56 Moby Thesaurus words for "gussy up":
   adorn, array, beautify, become one, bedeck, bedizen, blazon, color,
   dandify, deck, deck out, decorate, dizen, doll up, dress, dress up,
   embellish, emblazon, embroider, enrich, fancy up, fig out, fix up,
   furbish, garnish, get up, glamorize, grace, ornament, overdress,
   paint, prank, prank up, preen, prettify, pretty up, primp,
   primp up, prink, prink up, rag out, redecorate, redo, refurbish,
   set off, set out, slick, slick up, smarten, smarten up, spiff,
   spruce up, titivate, trick out, trick up, trim