workman vs roundsman

workman and roundsman both are nouns.

Word	Noun	Adjective	Verb	Adverb
workman	Yes	No	No	No
roundsman	Yes	No	No	No

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

workman: an employee who performs manual or industrial labor
roundsman: a workman employed to make rounds (to deliver goods or make inspections or so on)

workman (noun)	roundsman (noun)
an employee who performs manual or industrial labor	a workman employed to make rounds (to deliver goods or make inspections or so on)