The Collaborative International Dictionary
Armisonant
Armisonant \Ar*mis"o*nant\, Armisonous \Ar*mis"o*nous\, a. [L. armisonus; arma arms + sonare (p. pr. sonans) to sound.] Rustling in arms; resounding with arms. [Obs.]
Wiktionary
armisonant
a. (context obsolete nonce poetic English) resound with arms, or weapons.