The Collaborative International Dictionary of English v.0.48:

Swiss \Swiss\, n. sing. & pl. [F. Suisse, of German origin. Cf.
   Switzer.]
   A native or inhabitant of Switzerland; a Switzer; the people
   of Switzerland.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Swiss \Swiss\, a.
   Of or pertaining to Switzerland, or the people of
   Switzerland.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Swiss
    adj 1: of or relating to Switzerland or its people or culture;
           "the Swiss army"
    n 1: the natives or inhabitants of Switzerland [syn: Swiss,
         Swiss people]