The Collaborative International Dictionary of English v.0.48:

Unattired \Unattired\
   See attired.

WordNet (r) 3.0 (2006):

unattired
    adj 1: having removed clothing [syn: unappareled, unattired,
           unclad, undressed, ungarbed, ungarmented]

Moby Thesaurus II by Grady Ward, 1.0:

21 Moby Thesaurus words for "unattired":
   clothesless, decollete, disrobed, en deshabille, garbless,
   garmentless, half-clothed, in dishabille, low-cut, nudish,
   raimentless, strapless, topless, uncased, unclad, unclothed,
   undraped, undressed, ungarbed, ungarmented, unrobed