🔼The name Teresh in the Bible
There only one man named Teresh in the Bible, and he is mentioned twice. Teresh, and his colleague gatekeeper Bigthan(a), had somehow become disgruntled with their boss, the Persian emperor Ahasuerus, and planned to assassinate him (Esther 2:21). Fortunately for Ahasuerus, Mordecai, the uncle of queen Esther, heard of the plot and told his niece about it. Teresh and Bigthan were arrested, tried and executed but Mordecai was forgotten.
A while later during a sleepless night, the king reviewed the plot of Teresh and Bigthan and decided to bestow belated honors on Mordecai (Esther 6:2). This led to the confusion that fueled general Haman's already substantial hate of the Jews, which led to the near holocaust which is remembered during Purim up until today.
🔼Etymology and meaning of the name Teresh
The name Teresh is Persian and doesn't seem to mean anything in Hebrew. However, this name תרש or Teresh does look like a truncated form of the name תרשיש or Tarshish, which besides the name of a famous city was also a Persian personal name (Esther 1:14).
Our name is also suspiciously similar to the first element of the honorable Persian title תרשתא tirshatha, usually translated with "governor" (Ezra 2:63, Nehemiah 7:65).
BDB Theological Dictionary reports that the Persian title may have to do with the element tarsta, meaning the feared or revered, but the name Teresh may come from tarsa, a noun that means Desired.
Alfred Jones (Dictionary of Old Testament Proper Names) appears to go with tarsta and translates our name with Severe, Austere. What sources the scholars behind NOBSE Study Bible Name List have at their disposal isn't clear, but they translate our name with an inexplicable Dry.