Default on refers to a failure to fulfill an obligation or promise. Some common antonyms for default on include meet, fulfill, honor, satisfy, and keep. Meeting one's obligations is an important part of being a responsible and reliable person, and failing to do so can have serious consequences. When someone defaults on a loan or other financial obligation, for example, it can damage their credit rating and make it harder for them to obtain credit in the future. On the other hand, when someone fulfills their promises and meets their obligations, they build trust and integrity, which can lead to greater opportunities and success in life.