exactness

noun

1. Correspondence with fact or truth: accuracy, correctness, exactitude, fidelity, truth, veraciousness, veracity, veridicality, verity. See true/false.
2. Freedom from error: accuracy, accurateness, correctness, exactitude, preciseness, precision, rightness. See correct/incorrect.

The noun has one meaning:

Meaning #1: the quality of being exact
  Synonym: exactitude
  Antonym: inexactness (meaning #1)