A numbnuts is a person of 'a certain age', i.e., old enough to know better, who behaves like a total shit or shithead.  A jerk, a fool, a putz, schmuck, asshole, etc.
Mike and Louise behaved like complete numbnuts over that issue.  They got mad and over-reacted, just like the numbnuts that they are.
by Athelstan Spilhaus IV September 10, 2006
 Get the numbnutsmug.
Get the numbnutsmug. "I hear that Johnny shot himself in the head while cleaning out a loaded shotgun before he headed out for the opening of dear season, what a numbnut!"
by btezra October 25, 2002
 Get the numbnutmug.
Get the numbnutmug. by Italian Stallion November 17, 2004
 Get the numbnutsmug.
Get the numbnutsmug. This word is Self-Explanatory
by Stu August 13, 2004
 Get the numbnutsmug.
Get the numbnutsmug. by Jockular Strapping June 7, 2005
 Get the numbnutismmug.
Get the numbnutismmug. by Red December 13, 2003
 Get the numbnutsmug.
Get the numbnutsmug. by maximorph April 23, 2003
 Get the numbnutmug.
Get the numbnutmug.