Source : Webster's Revised Unabridged Dictionary (1913)

Knockabout \Knock"a*bout`\, n.
   1. (Naut.) A small yacht, generally from fifteen to
      twenty-five feet in length, having a mainsail and a jib.
      All knockabouts have ballast and either a keel or
      centerboard. The original type was twenty-one feet in
      length. The next larger type is called a raceabout.

   2. A knockabout performer or performance. [Theat. Slang]

   3. A man hired on a sheep station to do odd jobs. [Colloq.,
      Australia]

Knockabout \Knock"a*bout`\, a.
   1. Marked by knocking about or roughness.

   2. Of noisy and violent character. [Theat. Slang]

   3. Characterized by, or suitable for, knocking about, or
      traveling or wandering hither and thither.

   4. That does odd jobs; -- said of a class of hands or
      laborers on a sheep station. [Collog., Australia]

Source : WordNet®

knockabout
     adj 1: full of rough and exuberant animal spirits; "boisterous
            practical jokes"; "knockabout comedy" [syn: {boisterous}]
     2: suitable for rough use; "a knockabout overcoat"; "a
        knockabout old car"
     n : a sloop with a simplified rig and no bowsprit