brain·ish /ˈbrenɪʃ/
  Brain·ish, a. Hot-headed; furious. [R.]
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  brainish
       adj : characterized by undue haste and lack of thought or
             deliberation; "a hotheaded decision"; "liable to such
             impulsive acts as hugging strangers"; "an impetuous
             display of spending and gambling"; "madcap escapades";
             (`brainish' is archaic) [syn: hotheaded, impulsive,
              impetuous, madcap, tearaway(a)]