expression, noun
not writing or visiting someone; losing touch
Idiomatic expression literally meaning 'weasel's path', used when someone stops communicating or visiting, as if they have disappeared like a weasel. Often used in the phrase いたちの道を切る (to cut off contact).
彼とはいつの間にかいたちの道になってしまった。
Before I knew it, I had lost touch with him.
いたちの道を切るつもりはないけど、最近忙しくて連絡できていない。
I don't intend to cut off contact, but I've been too busy to get in touch lately.
音信不通 is a more formal, direct term for being out of contact, while いたちの道 is a figurative, somewhat old-fashioned expression.
Literally 'weasel's path'. The weasel is associated with disappearing suddenly in Japanese folklore, giving rise to this idiom for cutting off contact.