The Collaborative International Dictionary of English v.0.48:

Burning \Burn"ing\, a.
   1. That burns; being on fire; excessively hot; fiery.
      [1913 Webster]

   2. Consuming; intense; inflaming; exciting; vehement;
      powerful; as, burning zeal.
      [1913 Webster]

            Like a young hound upon a burning scent. --Dryden.
      [1913 Webster]

   Burning bush (Bot.), an ornamental shrub (Euonymus
      atropurpureus), bearing a crimson berry.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Euonymin \Eu*on"y*min\, n. (Med.)
   A principle or mixture of principles derived from Euonymus
   atropurpureus, or spindle tree.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Euonymus atropurpureus
    n 1: deciduous shrub having purple capsules enclosing scarlet
         seeds [syn: wahoo, burning bush, Euonymus
         atropurpureus]