Source : Webster's Revised Unabridged Dictionary (1913)

Jackass \Jack"ass`\, n. [2d jack + ass.]
   1. The male ass; a donkey.

   2. A conceited dolt; a perverse blockhead.

   {Jackass bark} (Naut.), a three-masted vessel, with only the
      foremast square-rigged; a barkentine.

   {Jackass deer} (Zo["o]l.), the koba.

   {Jackass hare}, {Jackass rabbit} (Zo["o]l.). See {Jack
      rabbit}, under 2d {Jack}, n.

   {Jackass penguin} (Zo["o]l.), any species of penguin of the
      genus {Spheniscus}, of which several are known. One
      species ({S. demersus}) inhabits the islands near the Cape
      of Good Hope; another ({S. Magellanicus}) is found at the
      Falkland Islands. They make a noise like the braying of an
      ass; -- hence the name.

   {Laughing jackass}. (Zo["o]l.) See under {Laughing}.