germ vs germinal

germ is a noun but germinal is not a noun.

Word	Noun	Adjective	Verb	Adverb
germ	Yes	No	No	No
germinal	No	Yes	No	No

germ (noun)	germinal (noun)
a minute life form (especially a disease-causing bacterium); the term is not in technical use
a small apparently simple structure (as a fertilized egg) from which new tissue can develop into a complete organism
anything that provides inspiration for later work

germ (adjective)	germinal (adjective)
	containing seeds of later development