What is "yiush"

Yiush ("despair") is a concept in the Talmud regarding a Jew who loses an object (aveidoh) and another Jew finds it and the person who lost it is determined to have given up on the object. The general rule is that the original's owners "yiush" (giving up hope on finding the object) releases the object into the public domain, thereby allowing a finder of the object to keep it and releasing the finder from the obligation to return it to the original owner.

There is:

• "Yiush shelo m'daas" meaning a person declares hope lost without knowledge (or awareness of what happened to the lost object.)
• "Yiush m'daas" meaning hope is declared lost with knowledge (or the intent of the owner to give up possession.)