Thank you goowy, vidqun and kaleb. This is all very helpful and interesting.
It means "shrewd" in the sense of "prudence" in clever knowledge and sight, usually in navigation.
This definition of aroom in particular seems to be well aligned with the general gnostic interpretation of the snake, which I was reading into the other day.
Coincidentally, Taze Russell seems to have been greatly influenced by the Freemason line of thought, of which it burrowed much from the gnostic one.