WordWeb Online

1. With the head before the body
   "the runner slid headlong into third base";
   - headfirst
    
2. At breakneck speed
   "burst headlong through the gate";
   - precipitately
    
3. In a hasty and foolhardy manner
   "he fell headlong in love with his cousin";
   - rashly

1. Excessively quick
   "a headlong rush to sell";
   - hasty, Gadarene, gadarene
    
2. With the head foremost
   "a headlong dive into the pool";
   - headfirst

See also: forward, hurried

Encyclopedia: Headlong