verb vs participial

verb and participial both are nouns.

Word	Noun	Adjective	Verb	Adverb
verb	Yes	No	No	No
participial	Yes	Yes	No	No

As nouns, participial is a hyponym of verb; that is, participial is a word with a more specific, narrower meaning than verb:

verb: the word class that serves as the predicate of a sentence
participial: a non-finite form of the verb; in English it is used adjectivally and to form compound tenses

verb (noun)	participial (noun)
a content word that denotes an action, occurrence, or state of existence	a non-finite form of the verb; in English it is used adjectivally and to form compound tenses
the word class that serves as the predicate of a sentence

verb (adjective)	participial (adjective)
	of or relating to or consisting of participles