argus-eyed vs watchful

argus-eyed and watchful both are adjectives.

Word	Noun	Adjective	Verb	Adverb
argus-eyed	No	Yes	No	No
watchful	No	Yes	No	No

As adjectives, argus-eyed and watchful are synonyms defined as:

argus-eyed and watchful: carefully observant or attentive; on the lookout for possible danger

Other synonyms of argus-eyed include open-eyed, vigilant, wakeful.

argus-eyed (adjective)	watchful (adjective)
carefully observant or attentive; on the lookout for possible danger	engaged in or accustomed to close observation
having very keen vision	experiencing or accompanied by sleeplessness
	carefully observant or attentive; on the lookout for possible danger