unusedAccountValidityDays

The user account expiration limit, in days, after which a new account that hasn't signed in is no longer usable. To reset the account after that time limit, you must call AdminCreateUser again, specifying "RESEND" for the MessageAction parameter. The default value for this parameter is 7.

If you set a value for TemporaryPasswordValidityDays in PasswordPolicy, that value will be used, and UnusedAccountValidityDays will be no longer be an available parameter for that user pool.