season vs toughen

season is a noun but toughen is not a noun.

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

As verbs, toughen is a hypernym of season; that is, toughen is a word with a broader meaning than season:

season (noun)	toughen (noun)
one of the natural periods into which the year is divided by the equinoxes and solstices or atmospheric conditions
a recurrent time marked by major holidays
a period of the year marked by special events or activities in some field

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