Source : Webster's Revised Unabridged Dictionary (1913)

Astrut \A*strut"\, a. & adv.
   1. Sticking out, or puffed out; swelling; in a swelling
      manner. [Archaic]

            Inflated and astrut with self-conceit. --Cowper.

   2. In a strutting manner; with a strutting gait.