-ess

(Greek -issa > Late Latin -issa > Old French -esse > Middle English -esse: a suffix that forms nouns meaning a female +++, as in lioness, tigress, heiress, hostess, and sculptress)

When -ess is added to a noun ending in -tor, -ter, the vowel before r is generally elided (eliminated or left out), as in actress (actor + -ess); and such a derivative with the ending -tress (often equivalent to French ) is usually considered a reduced form of Latin -trix, -tricem and popularly regarded as the equivalent of -tor + -ess.

In Middle English many words in -esse were adopted from French; such as, countess, duchess, mistress, and princess, or formed on nouns in -er; such as, enchantress and sorceress.

—Based on information presented in
The Barnhart Dictionary of Etymology, Robert K. Barnhart, Editor;
The H.W. Wilson Company; Bronxville, New York; 1988; page 343.

The suffix -ess is diminishing from English usage, with trends or tendencies toward avoiding any unnecessary references to gender or sexual categorizing (feminine or masculine.

The suffixes -er and -or are no longer gender-specific in modern English: an author or manager, like a doctor or writer, may be male or female, so the words authoress and manageress are considered redundant.

Some -ess words remain in use; for example, heiress and actress, although actor is being used more often now for both men and women.

tigress
1. A female tiger.
2. A fierce, aggressive, or audacious woman.
3. A woman resembling a tiger, as in fierceness or courage.
Titaness, titaness (s) (noun); Titanesses, titanesses (pl)
1. When capitalized, the female members of the older gods who preceded the Olympians and were the children of Uranus (Heaven) and Gaia (Earth): The Titanesses were also of great strength and size just as their brothers were.
2. When not capitalized, a woman of very great strength, intellect, or importance: More and more women in our modern times are becoming titanesses as they take the places of men in politics, businesses, and other areas of authority.
tyranness
The female form of tyrant; a female tyrant.
veteraness
A female veteran.
waitress