Jackass Share definition Flag Any officer of the United States Army who graduated from West Point. This definition originates due to the fact that the school mascot is indeed a donkey.. aka .. YOU GUESSED IT ... A JACKASS "THe new LT is from Westpoint." "Great just what we need another Jackass!!!" Jackass by L|_|<45 December 13, 2006 Get the Jackass mug.