Book of Malachi in Wikipedia

Malachi (or Malachias, מַלְאָכִי, Malʾaḫi, Mál'akhî) is a book of the Hebrew Bible, written by the prophet Malachi. Possibly this is not the name of the author, since Malachi means 'my messenger' or 'my angel' in Hebrew. The last of the twelve minor prophets (canonically), the final book of the Hebrew Bible in Christian, but not Jewish tradition is commonly attributed to a prophet by the name of Malachi. Although the appellation Malachi has frequently been understood as a proper name, its Hebrew meaning is simply "My [i.e., God's] messenger" (or 'His messenger' in the Septuagint). This sobriquet occurs in the superscription at 1:1 and in 3:1, although it is highly unlikely that the word refers to the same character in both of these references. Thus, there is substantial debate regarding the identity of the author of the biblical book of Malachi. The Jewish Targum identifies Ezra (or Esdras) as the author of Malachi. St. Jerome suggests this may be because Ezra is seen as an intermediary between the prophets and the 'great synagogue'. There is, however, no historical evidence to support this claim...

Link: https://en.wikipedia.org/wiki/Book_of_Malachi