overspill vs flowing

overspill and flowing both are nouns.

Word	Noun	Adjective	Verb	Adverb
overspill	Yes	No	No	No
flowing	Yes	Yes	No	No

As nouns, flowing is a hypernym of overspill; that is, flowing is a word with a broader meaning than overspill:

overspill: the occurrence of surplus liquid (as water) exceeding the limit or capacity
flowing: the motion characteristic of fluids (liquids or gases)

Other hypernyms of overspill include flow.

overspill (noun)	flowing (noun)
the occurrence of surplus liquid (as water) exceeding the limit or capacity	the motion characteristic of fluids (liquids or gases)
the relocation of people from overcrowded cities; they are accommodated in new houses or apartments in smaller towns

overspill (adjective)	flowing (adjective)
	designed or arranged to offer the least resistance to fluid flow