Is a real word or just combining form?

"Real" is a real word! It's an adjective meaning genuine, actual, or authentic.

However, you might be thinking of "re" which is often used as a combining form meaning "again" or "back." For example:

* re-read (read again)

* re-write (write again)

* re-enter (enter again)

Let me know if you were wondering about "re" or something else!