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]