it has disappeared entirely/ neither visible nor findable

Forbidden to be found. By extension: disappeared entirely; not present. (The original source is in the verses Deuteronomy 16:4: "No leaven shall be seen with you in all your territory for seven days," and likewise Exodus 12:19: "For seven days, no leaven shall be found in your houses.")

("What is the difference between the first Passover and the second? – The first is forbidden with 'shall not be seen and shall not be found', and the second, matzah and leaven are together" – Pesachim 9:3, and similarly: "I can no longer hide you... a Jew in the village—forbid it, absolutely forbid it, in the sense of 'shall not be seen and shall not be found'. There they are now meticulous as a hair's breadth" – Bialik / The Shamed Trumpet, 134)

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