The word "de-feasance" refers to the act of canceling, revoking or nullifying an agreement or contract. In contrast, its antonyms are words that refer to actions that preserve, uphold, or maintain the validity of an agreement or contract. Some antonyms of de-feasance include compliance, adherence, observance, and fulfillment. Compliance refers to the act of conforming to the terms of an agreement, while adherence refers to staying loyal to the terms of an agreement. Observance means following the rules, customs or traditions set in an agreement. Finally, fulfillment means carrying out the terms of an agreement completely, without any deviation. Understanding the antonyms of de-feasance can help individuals uphold the terms of their contracts and agreements.