Wordnet 3.0
NOUN (2)
1. 
 a part of a city that is notorious for gambling dens and brothels and saloons and riotous night life (especially the waterfront of San Francisco after the gold rush of 1849); 
- Example: "we'll tolerate no Barbary Coast in this city!"2. 
 the Mediterranean coast of northern Africa that was famous for its Moorish pirates; 
WordNet (r) 3.0 (2006):
Barbary Coast
    n 1: a part of a city that is notorious for gambling dens and
         brothels and saloons and riotous night life (especially the
         waterfront of San Francisco after the gold rush of 1849);
         "we'll tolerate no Barbary Coast in this city!"
    2: the Mediterranean coast of northern Africa that was famous
       for its Moorish pirates