road agent vs highwayman

road agent and highwayman both are nouns.

Word	Noun	Adjective	Verb	Adverb
road agent	Yes	No	No	No
highwayman	Yes	No	No	No

As nouns, road agent and highwayman are synonyms defined as:

road agent and highwayman: a holdup man who stops a vehicle and steals from it

Other synonyms of road agent include highjacker, hijacker.

road agent (noun)	highwayman (noun)
a holdup man who stops a vehicle and steals from it	a holdup man who stops a vehicle and steals from it