Definify.com
Webster 1913 Edition
Avengeress
A-ven′ger-ess
,Noun.
 A female avenger. 
[Obs.] 
Spenser.
 Webster 1828 Edition
Avengeress
AVENG'ERESS
,Noun.
  Definition 2025
avengeress
avengeress
English
Noun
avengeress (plural avengeresses)
-  (rare) A female avenger.
- 1590, Edmund Spenser, The Faerie Queene, III-viii - That cruell Queene avengeresse
- 2004: Brian P. Levack, The Witchcraft Sourcebook, p. 323 - Here you see the torch of Althaea, the avengeress; she was a good sister, but a bad mother.
 
References
- avengeress in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913
- The Century Dictionary, The Century Co., New York, 1914