schoolma'am vs school teacher

schoolma'am and school teacher both are nouns.

Word	Noun	Adjective	Verb	Adverb
schoolma'am	Yes	No	No	No
school teacher	Yes	No	No	No

As nouns, school teacher is a hypernym of schoolma'am; that is, school teacher is a word with a broader meaning than schoolma'am:

Other hypernyms of schoolma'am include schoolteacher, adult female, woman.

schoolma'am (noun)	school teacher (noun)
a woman schoolteacher (especially one regarded as strict)	a teacher in a school below the college level