The Collaborative International Dictionary of English v.0.48:
Astrut \A*strut"\, a. & adv. 1. Sticking out, or puffed out; swelling; in a swelling manner. [Archaic] [1913 Webster] Inflated and astrut with self-conceit. --Cowper. [1913 Webster] 2. In a strutting manner; with a strutting gait. [1913 Webster]