Source : Webster's Revised Unabridged Dictionary (1913)

Breakfast \Break"fast\, v. i. [imp. & p. p. {breakfasted}; p.
   pr. & vb. n. {Breakfasting}.]
   To break one's fast in the morning; too eat the first meal in
   the day.

         First, sir, I read, and then I breakfast. --Prior.