See sobriety in Webster's New World College Dictionary
noun
the state or quality of being sober; specif.,
temperance or moderation, esp. in the use of alcoholic liquor
seriousness; sedateness
See sobriety in American Heritage Dictionary 4
(sə-brīˈĭ-tē, sō-)
noun
Gravity in bearing, manner, or treatment.
Moderation in or abstinence from consumption of alcoholic liquor or use of drugs: “three years of drug-free sobriety”(Ron Rosenbaum). See Synonyms at abstinence.