The term "feasibleness" refers to the possibility or likelihood of being achieved or accomplished. Some antonyms for the word "feasibleness" include impracticality, impossibility, unfeasibility, and impracticability. These words imply that something cannot be done or achieved, either because it is too difficult, impractical, or simply impossible. For example, if a project is deemed to have the quality of "impossibility," it means that it cannot be achieved, no matter how much effort is put into it. Similarly, if an idea is described as "impracticable," it suggests that it is not sensible to implement and cannot be accomplished.