The Collaborative International Dictionary of English v.0.48:

mulligan \mulligan\, mulligan stew \mulligan stew\n.
   1. A stew made typically of meat, vegetables, and any
      conveniently available ingredients; also, an Irish version
      of burgoo.

   Syn: Irish burgoo.
        [WordNet 1.5]

   2. (Golf) In informal and friendly games of golf, a
      permission to take another stroke without counting the
      previous stroke against the score, when a stroke was
      poorly played; a free stroke; as, to take a mulligan.
      [PJC]

WordNet (r) 3.0 (2006):

mulligan
    n 1: Irish version of burgoo [syn: mulligan stew, mulligan,
         Irish burgoo]