🔼The name Mispar in the Bible
There's only one man named Mispar in the Bible, and he's also called Mispereth (מספרת). He is one of the few men listed by name, who joined Zerubbabel and Jeshua the high priest in the second wave of returnees from the Babylonian exile back to Canaan (Ezra 2:2). Ezra calls this man Mispar but Nehemiah calls him Mispereth (Ezra 2;2, Nehemiah 7:7).
🔼Etymology of the name Mispar
The names Mispar and Mispereth both come from the word cluster that's formed around the noun ספר (seper), meaning book or more general: a writing:
The name Mispar is the same as the noun מספר (mispar), meaning number or recount, and the name Mispereth might simply be an older spelling of the feminine form of that noun. It's by no means unusual that men in the Bible have names that are really feminine nouns, or that women have names that are masculine nouns.
For a meaning of the name Mispar (and Mispereth) NOBSE Study Bible Name List reads Writing. Jones' Dictionary of Old Testament Proper Names has Number, "i.e. a few". BDB Theological Dictionary does not interpret either version of this name but does list them both under the word-cluster ספר (seper).