Definition of old testaments:
(n) :
(religion, chiefly Christianity) The first major part of the Christian Bible, covering events before the coming of Christ, corresponding roughly to the Jewish Tanakh. Usually subdivided into the categories of law, history, poetry (or wisdom books), and prophecy.
(adj) :
(often humorous) Reminiscent of the content of the Old Testament, or of the behavior of God in it; especially dramatic, violent or vengeful.