The Collaborative International Dictionary of English v.0.48:

Irish \I*rish"\, n. sing. & pl.
   1. pl. The natives or inhabitants of Ireland, esp. the Celtic
      natives or their descendants.
      [1913 Webster]

   2. The language of the Irish; also called Irish Gaelic or
      the Hiberno-Celtic.
      [1913 Webster +PJC]

   3. An old game resembling backgammon.
      [1913 Webster]

   get one's Irish up to become angry.
      [PJC] Irish American

WordNet (r) 3.0 (2006):

Irish Gaelic
    n 1: the Celtic language of Ireland [syn: Irish, Irish
         Gaelic]