WordWeb Online

1. Marked by the exercise of good judgment or common sense in practical matters
   "heady use of one's money"
   - judicious, wise
    
2. Extremely exciting as if by alcohol or a narcotic
   - intoxicating
    
3. Marked by defiant disregard for danger or consequences
   "heady enough to try to seize the gun from the hijacker"
   - foolhardy, rash, reckless

Derived forms: headiest, headier

See also: bold, exciting, head, prudent

Encyclopedia: Heady