NOUN (1)

1. a woman's garment that exposes the shoulders and has no shoulder straps;


ADJECTIVE (1)

1. having no straps;
- Example: "a strapless evening gown"

WordNet (r) 3.0 (2006):

strapless
    adj 1: having no straps; "a strapless evening gown"
    n 1: a woman's garment that exposes the shoulders and has no
         shoulder straps

Moby Thesaurus II by Grady Ward, 1.0:

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