season vs Christmas

season and Christmas both are nouns.

Word	Noun	Adjective	Verb	Adverb
season	Yes	No	Yes	No
Christmas	Yes	No	No	No

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

season (noun)	Christmas (noun)
one of the natural periods into which the year is divided by the equinoxes and solstices or atmospheric conditions	a Christian holiday celebrating the birth of Christ; a quarter day in England, Wales, and Ireland
a recurrent time marked by major holidays	period extending from Dec. 24 to Jan. 6
a period of the year marked by special events or activities in some field

season (verb)	Christmas (verb)
make healthy
make more temperate, acceptable, or suitable by adding something else
lend flavor to