geyser vs overflow

geyser and overflow both are nouns.

Word	Noun	Adjective	Verb	Adverb
geyser	Yes	No	Yes	No
overflow	Yes	No	Yes	No

As verbs, overflow is a hypernym of geyser; that is, overflow is a word with a broader meaning than geyser:

Other hypernyms of geyser include brim over, overrun, run over, well over.

geyser (noun)	overflow (noun)
a spring that discharges hot water and steam	a large flow
	the occurrence of surplus liquid (as water) exceeding the limit or capacity

geyser (verb)	overflow (verb)
to overflow like a geyser	overflow with a certain feeling
	flow or run over (a limit or brim)