WordNet (r) 3.0 (2006):

sportswear
    n 1: attire worn for sport or for casual wear [syn:
         sportswear, athletic wear, activewear]

Moby Thesaurus II by Grady Ward, 1.0:

46 Moby Thesaurus words for "sportswear":
   apparel, array, attire, bedizenment, clothes, clothing, costume,
   drapery, dress, dressing, dry goods, duds, fashion, fatigues,
   feathers, fig, garb, garments, gear, guise, habiliment, habit,
   investiture, investment, leather goods, leatherware, linen, linens,
   napery, rags, raiment, robes, soft goods, sporting goods, style,
   textiles, threads, togs, toilette, trim, vestment, vesture, wear,
   wearing apparel, white goods, yard goods