Abarim Publications' online Biblical Hebrew Dictionary
סרח
The verb סרח (sarah) means to go free. It occurs in Arabic where it may denote the free-roaming of camels or the letting loose of one's hair. In the Bible this verb occurs in much the same way. It may denote folks lounging freely (Amos 6:4) or the abundantly overhanging of tent covers (Exodus 26:12). In Jeremiah 49:7, the prophet wonders if wisdom (the disciplined containment of understanding) has gone haywire.
This verb comes with one derivative, the masculine noun סרח (serah), meaning excess. It occurs only once, in Exodus 26:12.