Yes, season is playable
...and is worth 7 points.
Found in the following dictionaries
Enable (Words with friends)
SOWPODS (Collins Scrabble Words)
OTCWL2014 (NASPA Word List 2014)
TWL06 (NASPA List 2006)
"Season" Definition
noun
A period of time: gone for a season.
A recurrent period characterized by certain occurrences, occupations, festivities, or crops: the holiday season; tomato season.
A suitable, natural, or convenient time: a season for merriment.
One of the four natural divisions of the year, spring, summer, fall, and winter, in the North and South Temperate zones. Each season, beginning astronomically at an equinox or solstice, is characterized by specific meteorological or climatic conditions.
The two divisions of the year, rainy and dry, in some tropical regions.
idiom
In season At the right moment; opportunely.
In season Available or ready for eating or other use.
In season In heat. Used of animals.
In season Legally permitted to be caught or hunted during a specified period.
Out of season Not at the right or proper moment; inopportunely.
verb-transitive
To accustom or inure; harden: troops who had been seasoned in combat. See Synonyms at harden.
To add zest, piquancy, or interest to: seasoned the lecture with jokes.
To improve or enhance the flavor of (food) by adding salt, spices, herbs, or other flavorings.
To render competent through trial and experience: a lawyer who had been seasoned by years in the trial courts.
verb-intransitive
To become usable, competent, or tempered.
verb
To give (food) more flavor or zest by adding or savory ingredients.
To give a distinctive quality to as if by seasoning.
To qualify by admixture .
To treat (as wood or a skillet) so as to prepare for use.