The Collaborative International Dictionary of English v.0.48:

Duds \Duds\, n. pl. [Scot. dud rag, pl. duds clothing of
   inferior quality.]
   1. Old or inferior clothes; tattered garments. [Colloq.]
      [1913 Webster]

   2. Effects, in general.[Slang]
      [1913 Webster]

WordNet (r) 3.0 (2006):

duds
    n 1: informal terms for clothing [syn: togs, threads,
         duds]

Moby Thesaurus II by Grady Ward, 1.0:

44 Moby Thesaurus words for "duds":
   apparel, array, attire, bedizenment, clothes, clothing, costume,
   drapery, dress, dressing, fashion, fatigues, feathers, fig, frock,
   garb, garment, garments, gear, gown, guise, habiliment,
   habiliments, habit, investiture, investment, linen, rag, rags,
   raiment, robe, robes, sportswear, style, tatters, things, threads,
   togs, toilette, trim, vestment, vesture, wear, wearing apparel