Source : Webster's Revised Unabridged Dictionary (1913)

Foolhardy \Fool"har`dy\, a. [OF. folhardi. See {Fool} idiot, and
   {Hardy}.]
   Daring without judgment; foolishly adventurous and bold.
   --Howell.

   Syn: Rash; venturesome; venturous; precipitate; reckless;
        headlong; incautious. See {Rash}.

Source : WordNet®

foolhardy
     adj : marked by unthinking boldness; with defiant disregard for
           danger or consequences; "foolhardy enough to try to
           seize the gun from the hijacker"; "became the fiercest
           and most reckless of partisans"-Macaulay; "a reckless
           driver"; "a rash attempt to climb the World Trade
           Center" [syn: {rash}, {reckless}]
     [also: {foolhardiest}, {foolhardier}]