overwatch vs vigil

overwatch and vigil both are nouns.

Word	Noun	Adjective	Verb	Adverb
overwatch	Yes	No	No	No
vigil	Yes	No	No	No

As nouns, vigil is a hypernym of overwatch; that is, vigil is a word with a broader meaning than overwatch:

overwatch: surveillence by a unit within a video game which would cause the unit to make an action in response to an enemy unit's action
vigil: a purposeful surveillance to guard or observe

Other hypernyms of overwatch include watch.

overwatch (noun)	vigil (noun)
surveillence by a unit within a video game which would cause the unit to make an action in response to an enemy unit's action	a purposeful surveillance to guard or observe
	the rite of staying awake for devotional purposes (especially on the eve of a religious festival)
	a period of sleeplessness