The Collaborative International Dictionary of English v.0.48:

Roughcast \Rough`cast"\, v. t.
   1. To form in its first rudiments, without revision,
      correction, or polish. --Dryden.
      [1913 Webster]

   2. To mold without nicety or elegance; to form with
      asperities and inequalities.
      [1913 Webster]

   3. To plaster with a mixture of lime and shells or pebbles;
      as, to roughcast a building.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Roughcast \Rough"cast`\, n.
   1. A rude model; the rudimentary, unfinished form of a thing.
      [1913 Webster]

   2. A kind of plastering made of lime, with a mixture of
      shells or pebbles, used for covering buildings. --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

roughcast
    n 1: a coarse plaster for the surface of external walls
    2: a rough preliminary model
    v 1: shape roughly
    2: apply roughcast to; "roughcast a wall"
    3: hew roughly, without finishing the surface; "rough-hew stone
       or timber" [syn: rough-hew, roughcast]