overnighter vs guest

overnighter and guest both are nouns.

Word	Noun	Adjective	Verb	Adverb
overnighter	Yes	No	No	No
guest	Yes	No	No	No

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

overnighter (noun)	guest (noun)
a small traveling bag to carry clothing and accessories for staying overnight	(computer science) any computer that is hooked up to a computer network
a guest who stays overnight	a visitor to whom hospitality is extended
	a customer of a hotel or restaurant etc.