I could use the words "law" and "Christ", but I don't want to.
Yes, and I'm asking why you don't want to use biblical (or English equivalence) vocabulary. The reason you gave is unconvincing.
I want to use the words "Torah" and "Messiah", because I perceive they are more precise to the original meanings.
Both the New and Old Testaments refers to the books of Moses as the "Law". The word "Torah" doesn't appear in the Bible as a reference to any part of the Bible. If the authors of the Bible didn't need that alleged precision, why do you? And, the word Torah is far from precise. Jews use the word Torah to refer to parts of the Talmud. And, Jews use the word Torah to refer to more biblical books than just the books of the Law. If you want precision, you'd say Pentateuch, but you don't.
How is "Messiah" any more precise than Christ? And, how can you possibly get more precise than the Bible's own language? If anything, you lose precision when you stray from biblical language.
I don't think you've given me your honest reason, yet. Why not?