boy vs ploughboy

boy and ploughboy both are nouns.

Word	Noun	Adjective	Verb	Adverb
boy	Yes	No	No	No
ploughboy	Yes	No	No	No

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

boy (noun)	ploughboy (noun)
a youthful male person	a boy who leads the animals that draw a plow
(ethnic slur) offensive and disparaging term for Black man
a friendly informal reference to a grown man
a male human offspring