1. 
[syn: slapper, spanker]
2.  a fore-and-aft sail set on the aftermost lower mast (usually the mizzenmast) of a vessel; 
The Collaborative International Dictionary of English v.0.48:
Spanker \Spank"er\ (sp[a^][ng]k"[~e]r), n.
   1. One who spanks, or anything used as an instrument for
      spanking.
      [1913 Webster]
   2. (Naut.) The after sail of a ship or bark, being a
      fore-and-aft sail attached to a boom and gaff; --
      sometimes called driver. See Illust. under Sail.
      --Totten.
      [1913 Webster]
   3. One who takes long, quick strides in walking; also, a fast
      horse. [Colloq.]
      [1913 Webster]
   4. Something very large, or larger than common; a whopper, as
      a stout or tall person. [Colloq.]
      [1913 Webster]
   Spanker boom (Naut.), a boom to which a spanker sail is
      attached. See Illust. of Ship.
      [1913 Webster]
The Collaborative International Dictionary of English v.0.48:
Spanker \Spank"er\, n.
   A small coin. [Obs. or Prov. Eng.]
   [1913 Webster]
WordNet (r) 3.0 (2006):
spanker
    n 1: a hitter who slaps (usually another person) with an open
         hand; "someone slapped me on the back and I turned to see
         who the slapper was"; "my father was the designated spanker
         in our family" [syn: slapper, spanker]
    2: a fore-and-aft sail set on the aftermost lower mast (usually
       the mizzenmast) of a vessel