road agent vs highjacker

road agent and highjacker both are nouns.

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

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

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

Other synonyms of road agent include highwayman, hijacker.

road agent (noun)	highjacker (noun)
a holdup man who stops a vehicle and steals from it	a holdup man who stops a vehicle and steals from it
	someone who uses force to take over a vehicle (especially an airplane) in order to reach an alternative destination