In "The Blue Scarab" in Dr. Thorndyke's Case-Book by R. Austin Freeman, Mr. Blowgrave, whose deed-box was stolen, was talking to Dr. Thorndyke:
"The story concerns my great-grandfather Silas Blowgrave, and his doings during the war with France. It seems that he commanded a privateer of which he and his brother Reuben were the joint owners, and that in the course of their last cruise they acquired a very remarkable and valuable collection of jewels. Goodness knows how they got them; not very honestly, I suspect, for they appear to have been a pair of precious rascals. Something has been said about the loot from a South American church or cathedral, but there is really nothing known about the affair.
I've never met the word "precious" with a bad adjective, does it mean "great" or something like that?