殻からを閉とざす

expression, godan verb (-su)

close up like an oyster; retire into one's shell

Rare idiomatic expression meaning to shut oneself off from others, like a clam closing its shell. More common alternatives include 殻に閉じこもる.

• 彼かれは失しつ恋れんしてから、すっかり殻からを閉とざしてしまった。

  After his heartbreak, he completely closed himself off from others.