Circumlocution (using many words where fewer would do):
* Brevity: Conciseness, shortness
* Directness: Straightforwardness, clarity
* Candor: Frankness, honesty
* Simplicity: Plainness, straightforwardness
* Conciseness: Being brief and to the point
Prestidigitation (sleight of hand, magic tricks):
* Truth: Reality, authenticity
* Honesty: Fairness, genuineness
* Reality: Truth, actuality
* Straightforwardness: Directness, clarity
* Naturalness: Spontaneity, lack of trickery
Words that work for both:
* Clarity: Clearness, lucidity
* Transparency: Openness, honesty
* Directness: Straightforwardness, clarity
The best antonym will depend on the specific context of your usage.