guest night vs eve

guest night and eve both are nouns.

Word	Noun	Adjective	Verb	Adverb
guest night	Yes	No	No	No
eve	Yes	No	No	No

As nouns, eve is a hypernym of guest night; that is, eve is a word with a broader meaning than guest night:

guest night: an evening when members of a club or college can bring their friends as guests
eve: the latter part of the day (the period of decreasing daylight from late afternoon until nightfall)

Other hypernyms of guest night include even, evening, eventide.

guest night (noun)	eve (noun)
an evening when members of a club or college can bring their friends as guests	the latter part of the day (the period of decreasing daylight from late afternoon until nightfall)
	the day before
	the period immediately before something