Under the ucc, is defined as "honesty in fact and the observance of reasonable commercial standards for fair dealing."

The answer is good faith. In section 1-201 of the Uniform Commercial Code good faith is defined normally as “honesty in fact in the conduct or transaction concerned.” Article 2 of the U.C.C. says “good faith in the case of a merchant means honesty in fact and the observance of reasonable commercial standards of fair dealing in the trade.” Similarly, Article 3 on negotiable instruments describes good faith as “honesty in fact and the observance of reasonable commercial standards of fair dealing,” an explanation which also applies to the provisions of Article 4 on bank deposits and collections and Article 4A on funds transfers. The U.C.C. enforces an obligation of good faith on the performance of every contract or duty under its purview. The law also generally necessitates good faith of fiduciaries and agents acting on behalf of their principals. There is also a necessity under the National Labor Relations Act that employers and unions bargain in good faith.