From the OP:

keywords in array 1 ... two more arrays that contain elements ...

You have chosen to ignore the original problem, and solve something similar, but different instead. Why?

It has been pointed out to you, that the unanchored regular expressions do not produce concrete matches. You have chosen to ignore this concern. Why?

Once more. The question was a fairly generic one. The only assumptions you are afforded is that inputs are in arrays and that some equality operator is available. Instead of giving a equally generic and sensible answer, you have resorted to a kludgy hack, in defiance of any criticism.

In this monastery, the tacit assumption—nay, an expectation—is that the participants are able to learn, or to advance the learning in others. Please consider this, and think of the value of your engagement so far.