belle vs missy

belle and missy both are nouns.

Word	Noun	Adjective	Verb	Adverb
belle	Yes	No	No	No
missy	Yes	No	No	No

As nouns, missy is a hypernym of belle; that is, missy is a word with a broader meaning than belle:

belle: a young woman who is the most charming and beautiful of several rivals
missy: a young female

Other hypernyms of belle include fille, girl, miss, young lady, young woman.

belle (noun)	missy (noun)
a young woman who is the most charming and beautiful of several rivals	a young female