Jackass \Jack"ass`\, n. [2d jack + ass.] [1913 Webster] 1. The male ass; a donkey. [1913 Webster] 2. A conceited dolt; a perverse blockhead; -- disparaging and offensive. [1913 Webster] {Jackass bark} (Naut.), a three-masted vessel, with only the foremast square-rigged; a barkentine. {Jackass deer} (Zool.), the koba. {Jackass hare}, {Jackass rabbit} (Zool.). See {Jack rabbit}, under 2d {Jack}, n. {Jackass penguin} (Zool.), any species of penguin of the genus {Spheniscus}, of which several are known. One species ({Spheniscus demersus}) inhabits the islands near the Cape of Good Hope; another ({Spheniscus Magellanicus}) is found at the Falkland Islands. They make a noise like the braying of an ass; -- hence the name. {Laughing jackass}. (Zool.) See under {Laughing}. [1913 Webster]