To this end, I had sat well back on the form, and while seeming to be busy with my sum, had held my slate in such a manner as to conceal my face: I might have escaped notice, had not my treacherous slate somehow happened to slip from my hand, and falling with an obtrusive crash, directly drawn every eye upon me; I knew it was all over now, and, as I stooped to pick up the two fragments of slate, I rallied my forces for the worst.
There are no more uses of "treacherous" in the book.
Show samples from other sources
The road through Afghanistan’s Kabul gorge is even more treacherous than the Road of Death in Bolivia.
It’s a gorgeous beach, but the waves are treacherous in the water.