female vs eonni

female and eonni both are nouns.

Word	Noun	Adjective	Verb	Adverb
female	Yes	Yes	No	No
eonni	Yes	No	No	No

As nouns, eonni is a hyponym of female; that is, eonni is a word with a more specific, narrower meaning than female:

female (noun)	eonni (noun)
an animal that produces gametes (ova) that can be fertilized by male gametes (spermatozoa)	an older other woman, especially a sister, used by a female
a person who belongs to the sex that can have babies

female (adjective)	eonni (adjective)
being the sex (of plant or animal) that produces fertilizable gametes (ova) from which offspring develop
for or pertaining to or composed of women or girls
characteristic of or peculiar to a woman