toughen vs season

toughen is not a noun while season is a noun.

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

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

Other hyponyms of toughen include harden.

toughen (noun)	season (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

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