The Collaborative International Dictionary of English v.0.48:

Liqueur \Li`queur"\ (l[-e]`k[~e]r"), n. [F. See Liquor.]
   An aromatic alcoholic cordial.
   [1913 Webster]

   Note: Some liqueurs are prepared by infusing certain woods,
         fruits, or flowers, in either water or alcohol, and
         adding sugar, etc. Others are distilled from aromatic
         or flavoring agents.
         [1913 Webster]

WordNet (r) 3.0 (2006):

liqueur
    n 1: strong highly flavored sweet liquor usually drunk after a
         meal [syn: liqueur, cordial]