The Collaborative International Dictionary of English v.0.48:

Assagai \As"sa*gai\, Assegai \As"se*gai\, n. [Pg. azagaia, Sp.
   azagaya, fr. a Berber word. Cf. Lancegay.]
   A spear used by tribes in South Africa as a missile and for
   stabbing, a kind of light javelin.
   [1913 Webster]

WordNet (r) 3.0 (2006):

assagai
    n 1: the slender spear of the Bantu-speaking people of Africa
         [syn: assegai, assagai]