colloquialism

“Shut up,” the hacker responded, using a Farsi colloquialism.

It is colloquialism; but it is such colloquialism as ghosts or vampires would use.

"Draw my mug," we might say, although translation does not go far to render that sort of colloquialism.

When it came to the point, our Neiden carriers, to use a colloquialism, climbed down abjectly.