stone-
stone-
prefix
1. very; completely: stone-blind; stone-cold.
[from stone in the sense of "like a stone"]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014