Colloquial exaggerated turn of phrase; almost "you could wipe them off the earth."
He was as familiar with colloquial English as he was with his own tongue.
Perrin was nettled, for he prided himself on his colloquial style.
In this way he acquired a colloquial knowledge of that language.
Mrs. Quabarl, to use a colloquial expression, was knocked off her perch.
That he ...