The Collaborative International Dictionary of English v.0.48:

Beautify \Beau"ti*fy\ (b[=u]"t[i^]*f[imac]), v. t. [imp. & p. p.
   Beautified (b[=u]"t[i^]*f[imac]); p. pr. & vb. n.
   Beautifying.] [Beauty + -fy.]
   To make or render beautiful; to add beauty to; to adorn; to
   deck; to grace; to embellish.
   [1913 Webster]

         The arts that beautify and polish life.  --Burke.
   [1913 Webster]

   Syn: To adorn; grace; ornament; deck; decorate.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Beautify \Beau"ti*fy\, v. i.
   To become beautiful; to advance in beauty. --Addison.
   [1913 Webster]

WordNet (r) 3.0 (2006):

beautify
    v 1: make more beautiful [syn: fancify, beautify,
         embellish, prettify] [ant: uglify]
    2: be beautiful to look at; "Flowers adorned the tables
       everywhere" [syn: deck, adorn, decorate, grace,
       embellish, beautify]
    3: 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]

Moby Thesaurus II by Grady Ward, 1.0:

60 Moby Thesaurus words for "beautify":
   adorn, array, become one, bedeck, bedizen, blazon, color,
   cultivate, dandify, deck, deck out, decorate, develop, dizen,
   doll up, dress, dress up, elaborate, embellish, emblazon,
   embroider, enrich, evolve, fig out, finish, fix up, furbish,
   garnish, glamorize, grace, gussy up, mature, ornament, paint,
   perfect, polish, prank, prank up, preen, prettify, pretty up,
   primp, primp up, prink, prink up, redecorate, redo, refine,
   refurbish, ripen, season, set off, set out, smarten, smarten up,
   spruce up, titivate, trick out, trick up, trim