Pentecost vs pentecostal

Pentecost is a noun but pentecostal is not a noun.

Word	Noun	Adjective	Verb	Adverb
Pentecost	Yes	No	No	No
pentecostal	No	Yes	No	No

Pentecost (noun)	pentecostal (noun)
seventh Sunday after Easter; commemorates the emanation of the Holy Spirit to the Apostles; a quarter day in Scotland
(Judaism) Jewish holy day celebrated on the sixth of Sivan to celebrate Moses receiving the Ten Commandments

Pentecost (adjective)	pentecostal (adjective)
	of or relating to or occurring at Pentecost
	of or relating to or characteristic of any of various Pentecostal religious bodies or their members