The Collaborative International Dictionary of English v.0.48:

Slicker \Slick"er\, n.
   That which makes smooth or sleek. Specifically:
   (a) A kind of burnisher for leather.
   (b) (Founding) A curved tool for smoothing the surfaces of a
       mold after the withdrawal of the pattern.
       [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Slicker \Slick"er\, n.
   A waterproof coat. [Western U.S.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

slicker
    n 1: a macintosh made from cotton fabric treated with oil and
         pigment to make it waterproof [syn: oilskin, slicker]
    2: a person with good manners and stylish clothing
    3: someone who leads you to believe something that is not true
       [syn: deceiver, cheat, cheater, trickster,
       beguiler, slicker]