Isolation
Cut Off, Blockade, Quarantine
noun, する verb
If you intercept trade and cut off a country from the rest of the world they'll be stuck in a state of isolation or if they have some kind of disease like zombie-itus, it's a quarantine.
しゃだん
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
サイトへのアクセスが遮断されました。
Access to the site has been cut off.