schoolmarm vs schoolmistress

schoolmarm and schoolmistress both are nouns.

Word	Noun	Adjective	Verb	Adverb
schoolmarm	Yes	No	No	No
schoolmistress	Yes	No	No	No

As nouns, schoolmarm and schoolmistress are synonyms defined as:

schoolmarm and schoolmistress: a woman schoolteacher (especially one regarded as strict)

Other synonyms of schoolmarm include mistress, schoolma'am.

schoolmarm (noun)	schoolmistress (noun)
a woman schoolteacher (especially one regarded as strict)	a woman schoolteacher (especially one regarded as strict)