Failure is the state or condition of not meeting a desirable or intended objective, and may be viewed as the opposite of success.
Is bankruptcy a business failure? Certainly not a success… I got a failing grade on my report card… Philosophers in the analytic tradition have suggested that failure is connected to the notion of an omission. Some act that could have lead to success didn’t happen and therefore, failure. The most famous failure in science, the “most famous failed experiment in history” because it did not detect the motion of the Earth through the luminiferous aether as had been expected. This failure to confirm the presence of the aether would later provide support for Albert Einstein’s special theory of relativity.
Recent US military failures and we learn nothing from them. Korea, Vietnam, and now Afghanistan; the major mistake made by President George W. Bush was not the invasion in 2001 to get rid of al-Qaeda, a successful operation, but his administration’s decision to use the occupation of Afghanistan to build a democratic government in a country that had no experience with free elections or interest in human rights. That effort has largely failed.