1610s, now obsolete, but prefered by purists for the sense "high and steep" over the later formation precipitous.
Online Etymology Dictionary, © 2010 Douglas Harper
Examples from the Web for precipitious
But, spurred by fears for his friend, he started downward for the precipitious trail leading directly towards it.
The hotel stood on a romantic elevation, a precipitious bluff, and commanded a magnificent view of the river and valley.Fifty Years In The Northwest
William Henry Carman Folsom