The Collaborative International Dictionary of English v.0.48:

knockabout \knock"a*bout`\, a.
   1. Marked by knocking about or roughness.
      [Webster 1913 Suppl.]

   2. Of noisy and violent character; marked by farce,
      pratfalls, and horseplay; as, knockabout comedy. [Theat.
      Slang]

   Syn: boisterous, slapstick.
        [Webster 1913 Suppl.]

   3. Characterized by, or suitable for, knocking about, or
      traveling or wandering hither and thither; suitable for
      use in rough activity; suited for everyday use; -- used
      especially of clothing.

   Syn: casual, everyday.
        [Webster 1913 Suppl.]

   4. That does odd jobs; -- said of a class of hands or
      laborers on a sheep station. [Collog., Australia]
      [Webster 1913 Suppl.]

The Collaborative International Dictionary of English v.0.48:

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; a
      sloop with a simplified rig and no bowsprit. 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.
      [Webster 1913 Suppl. + WordNet 1.5]

   2. A knockabout performer or performance. [Theat. Slang]
      [Webster 1913 Suppl.]

   3. A man hired on a sheep station to do odd jobs. [Colloq.,
      Australia]
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

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