san ‧ i ‧ ty /ˈsænəti, ˈsænɪti/ BrE AmE noun [uncountable]
[ Date: 1600-1700 ; Language: Latin ; Origin: sanitas 'health, sanity' , from sanus ; ⇨ ↑ sane ]
1 . the condition of being mentally healthy OPP insanity ⇨ sane :
I began to doubt his sanity.
She wondered if she was losing her sanity.
2 . when someone or something is being reasonable and sensible ⇨ sane :
Sanity appears to be returning to the stock market.
regain/get back/recover your sanity
I took a vacation to try to recover my sanity.