Bottomless pit.
abyss
To lure or entice by deception.
decoy
Daringly, often recklessly adventurous.
audacious
To firmly plant or establish.
engraft
Choice of one of two options.
allowable
permissible
Not aggravating but not interesting.
bland
possessing a friendly manner or temperament
genial
To start.
commence
Persistent in harshness or severity.
relentless
Facial expression.
countenance
incapable of change
invariable
Planned or accomplished usually by many people.
concerted
To keep something desirable visible but out of reach.
tantalize
To reduce or damage in quality or worth.
deteriorate
exceptionally steep
precipitous
To judge or conclude based on guesswork.
conjecture
Watch kept while others are normally sleeping.
vigil
emanate
watchful for danger or error
vigilant