discernment

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The act or process of exhibiting keen insight and good judgment.
• noun Keenness of insight and judgment.

from The Century Dictionary.

• noun The act of discerning.
• noun Acuteness of judgment; discrimination; a considerable power of perceiving differences in regard to matters of morals and conduct: as, the errors of youth often proceed from the want of discernment; also, the faculty of distinguishing; the exercise of this faculty.
• noun Synonyms Penetration, Discrimination, Discernment, judgment, intelligence, acuteness, acumen, clear-sightedness, sagacity, shrewdness, insight. Penetration, or insight, goes to the heart of a subject, reads the inmost character, etc. Discrimination marks the differences in what it finds. Discernment combines both these ideas.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act of discerning.
• noun The power or faculty of the mind by which it distinguishes one thing from another; power of viewing differences in objects, and their relations and tendencies; penetrative and discriminate mental vision; acuteness; sagacity; insight.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The ability to distinguish; judgement.
• noun Discrimination.
• noun To distinguish between things.
• noun To perceive differences that exist.
• noun The condition of understanding.
• noun Aesthetic discrimination; taste, appreciation.
• noun Perceptiveness.
• noun The ability to make wise judgements; sagacity.
• noun Discretion in judging objectively.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the cognitive condition of someone who understands
• noun delicate discrimination (especially of aesthetic values)
• noun perception of that which is obscure
• noun the mental ability to understand and discriminate between relations
• noun the trait of judging wisely and objectively