yardman vs manual laborer

yardman and manual laborer both are nouns.

Word	Noun	Adjective	Verb	Adverb
yardman	Yes	No	No	No
manual laborer	Yes	No	No	No

As nouns, manual laborer is a hypernym of yardman; that is, manual laborer is a word with a broader meaning than yardman:

yardman: a laborer hired to do outdoor work (such as mowing lawns)
manual laborer: someone who works with their hands; someone engaged in manual labor

Other hypernyms of yardman include jack, laborer, labourer.

yardman (noun)	manual laborer (noun)
a laborer hired to do outdoor work (such as mowing lawns)	someone who works with their hands; someone engaged in manual labor
worker in a railway yard