1 . insecurity
insection 切開;齒紋insecurity 不安全;易坍的狀態insensibility 不靈敏性
2 . precariousness
precarburization 預先碳化precariousness 不穩定;不安全;危險;根據不充分precast concrete 預制混凝土
3 . incertitude
inception 開始incertitude 不肯定;無把握;懷疑;不安全;不穩定inch by inch 漸漸
4 . not safe
we were warned that the bridge was not safe ., 我們得到警告說 , 這座橋不安全.