What does "murderess" mean?

Female equivalent of murderer: a woman who commits murder.

What is a synonym for "murderess"?

Common synonyms include: female killer, feminine agent noun, killer, murderer, slayer.

Pronounced //mɜːdəˈɹɛs//.

/mɜːdəˈɹɛs/ noun

noun ·Rare ·Advanced level

Noun

1
Female equivalent of murderer: a woman who commits murder. dated, feminine, form-of
"‘[…] Yet am I very fair, Kallikrates!’ / ‘I hate thee, murdress, and I have no wish to see thee.[…]’"
2
a woman murderer wordnet

"Surely no woman as beautiful as Mary Cavendish could be a murderess."

From Middle English morderes, from Old French morderesse, moeurdrese; equivalent to murder + -ess.