run out vs overflow

run out is not a noun while overflow is a noun.

Word	Noun	Adjective	Verb	Adverb
run out	No	No	Yes	No
overflow	Yes	No	Yes	No

As verbs, overflow is a hyponym of run out; that is, overflow is a word with a more specific, narrower meaning than run out:

Other hyponyms of run out include brim over, overrun, run over, well over.

run out (noun)	overflow (noun)
	a large flow
	the occurrence of surplus liquid (as water) exceeding the limit or capacity

run out (verb)	overflow (verb)
use up all one's strength and energy and stop working	overflow with a certain feeling
prove insufficient	flow or run over (a limit or brim)
exhaust the supply of
become used up; be exhausted
flow, run or fall out and become lost
flow off gradually
leave suddenly and as if in a hurry
lose validity