WordWeb Online

1. With the head foremost
   "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