The antonyms for the word "inviable" are "viable," "feasible," "practical," "possible," and "workable." If something is inviable, it means it is not capable of working, developing or surviving. Viable, on the other hand, means something that is workable, practicable, and can be achieved successfully. Therefore, if something is "viable," it means it is capable of being accomplished, developed, or sustained. Similarly, "feasible" implies that an idea or plan is practical and can be implemented successfully. "Possible" means something that is capable of happening or existing. Finally, "workable" refers to an idea or plan that is achievable and practical, and that can be put into practice without any major hurdles.