Source : Webster's Revised Unabridged Dictionary (1913)

Wildebeest \Wilde"beest`\, n. [D. wild wild + beeste beast.]
   (Zo["o]l.)
   The gnu.

Source : WordNet®

wildebeest
     n : large African antelope having a head with horns like an ox
         and a long tufted tail [syn: {gnu}]