tigress vs tiger

tigress and tiger both are nouns.

Word	Noun	Adjective	Verb	Adverb
tigress	Yes	No	No	No
tiger	Yes	No	No	No

As nouns, tiger is a hypernym of tigress; that is, tiger is a word with a broader meaning than tigress:

tigress: a female tiger
tiger: large feline of forests in most of Asia having a tawny coat with black stripes; endangered

Other hypernyms of tigress include Panthera tigris.

tigress (noun)	tiger (noun)
a female tiger	large feline of forests in most of Asia having a tawny coat with black stripes; endangered
	a fierce or audacious person