Source : Webster's Revised Unabridged Dictionary (1913)

Avaunt \A*vaunt"\, interj. [F. avant forward, fr. L. ab + ante
   before. Cf. {Avant}, {Advance}.]
   Begone; depart; -- a word of contempt or abhorrence,
   equivalent to the phrase ``Get thee gone.''

Avaunt \A*vaunt"\, v. t. & i.
   1. To advance; to move forward; to elevate. [Obs.] --Spenser.

   2. To depart; to move away. [Obs.] --Coverdale.

Avaunt \A*vaunt"\, v. t. & i. [OF. avanter; [`a] (L. ad) +
   vanter. See {Vaunt}.]
   To vaunt; to boast. [Obs.] --Chaucer.

Avaunt \A*vaunt"\, n.
   A vaunt; to boast. [Obs.] --Chaucer.