The Collaborative International Dictionary of English v.0.48:

getup \get"up\, get-up \get"-up\, n.
   1. General composition or structure; manner in which the
      parts of a thing are combined; arrangement; format;
      make-up; style of dress, etc. [Colloq.] --H. Kingsley.
      [1913 Webster]

   2. Specifically: A set of clothing (with accessories); as,
      what are you doing in that getup?; -- often used with
      implied disapproval or scorn. [informal] [WordNet sense 1]

   Syn: outfit, rig.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

getup
    n 1: a set of clothing (with accessories); "his getup was
         exceedingly elegant" [syn: outfit, getup, rig,
         turnout]

Moby Thesaurus II by Grady Ward, 1.0:

117 Moby Thesaurus words for "getup":
   accouterments, adventuresomeness, adventurousness, aggression,
   aggressiveness, ambitiousness, anatomy, architectonics,
   architecture, arrangement, assemblage, assembly, ballet skirt,
   bang, build, building, buildup, buskin, cap and bells, caparison,
   combination, composition, compound, conformation, constitution,
   construction, costume, creation, disguise, dress, drive, dynamism,
   embodiment, enterprise, enterprisingness, fabric, fabrication,
   fashion, fashioning, force, forcefulness, forging, form, format,
   formation, frame, furnishings, get-up-and-get, get-up-and-go, go,
   go-ahead, go-getting, go-to-itiveness, guise, gumption, harness,
   hustle, incorporation, initiative, junction, livery, make, makeup,
   making, manufacture, masquerade, mixture, mold, molding, motley,
   organic structure, organism, organization, outfit, pattern,
   patterning, pep, physique, piecing together, plan, production,
   punch, push, pushfulness, pushiness, pushingness, putting together,
   rig, setout, setup, shape, shaping, snap, sock, spirit, spunk,
   structure, structuring, syneresis, synthesis, tectonics, texture,
   things, tights, tissue, trappings, trousseau, turnout, tutu,
   up-and-comingness, venturesomeness, venturousness, vitality,
   wardrobe, warp and woof, weave, web