All 5 Uses

treacherous
in
Flora & Ulysses
(Edited)

The world is a treacherous place when you can't see.
p. 58.4 *

treacherous = dangerous
Flora didn't bother pointing out to him that the world was a treacherous place when you could see.
p. 58.4
And speaking of treacherousness, things were not, in any way, progressing as Flora had planned.
p. 58.5

treacherousness = being dangerous
Chapter 44: Her Treacherous Heart
p. 145.1 *

treacherous = guilty of betrayal or deception
But her heart, her treacherous heart, rose up joyfully inside of her at the sight of him.
p. 145.2

Definitions:

(1) (treacherous as in: the road is steep and treacherous)
dangerous -- often in a non-obvious way
(2) (treacherous as in: a scheming, treacherous assistant)
guilty of betrayal or deception or likely to betray or deceive
(3) (meaning too rare to warrant focus)