The Collaborative International Dictionary of English v.0.48:

Gabardine \Gab`ar*dine"\, Gaberdine \Gab`er*dine"\, n. [Sp.
   gabardina; cf. It. gavardina, OF. galvardine, calvardine,
   gavardine, galeverdine; perh. akin to Sp. & OF. gaban a sort
   of cloak or coat for rainy weather, F. caban great coat with
   a hood and sleeves, It. gabbano and perh. to E. cabin.]
   A coarse frock or loose upper garment formerly worn by Jews;
   a mean dress. --Shak.
   [1913 Webster]

WordNet (r) 3.0 (2006):

gabardine
    n 1: a firm durable fabric with a twill weave
    2: (usually in the plural) trousers made of flannel or gabardine
       or tweed or white cloth [syn: flannel, gabardine,
       tweed, white]
    3: a loose coverall (coat or frock) reaching down to the ankles
       [syn: duster, gaberdine, gabardine, smock, dust
       coat]