mum vs female parent

mum and female parent both are nouns.

Word	Noun	Adjective	Verb	Adverb
mum	Yes	Yes	No	No
female parent	Yes	No	No	No

As nouns, female parent is a hypernym of mum; that is, female parent is a word with a broader meaning than mum:

mum: informal terms for a mother
female parent: a woman who has given birth to a child (also used as a term of address to your mother)

Other hypernyms of mum include mother.

mum (noun)	female parent (noun)
secrecy	a woman who has given birth to a child (also used as a term of address to your mother)
informal terms for a mother
of China

mum (adjective)	female parent (adjective)
failing to speak or communicate etc when expected to