If in a certain coding language Cheater is coded as ejgcvgt, then how will Preacher be coded in that language?

Preacher is coded as rtgcejgt.

The rule shifts every letter forward by 2 places.

Cheater to ejgcvgt confirms C to e, h to j, e to g, a to c, t to v, r to t.

Apply +2 to Preacher: P to r, r to t, e to g, a to c, c to e, h to j, e to g, r to t.

That gives r t g c e j g t.

So Preacher = rtgcejgt.