headlong headlong /ˈhɛdˌlɔŋ/

adjective

1. With the head foremost  ( headfirst , headlong )
   with the head foremost
    A headfirst plunge down the stairs
   a headfirst plunge down the stairs
    A headlong dive into the pool
   a headlong dive into the pool
   
2. Excessively quick  ( headlong , Gadarene , hasty )
   excessively quick
    Made a hasty exit
   made a hasty exit
    A headlong rush to sell
   a headlong rush to sell
   

adverb

1. () With the head foremost  ( headfirst , headlong )
   with the head foremost
    The runner slid headlong into third base
   the runner slid headlong into third base
   
2. In a hasty and foolhardy manner  ( headlong , rashly )
   in a hasty and foolhardy manner
    He fell headlong in love with his cousin
   he fell headlong in love with his cousin
   
3. At breakneck speed  ( headlong , precipitately )
   at breakneck speed
    Burst headlong through the gate
   burst headlong through the gate