The term 'fails miserably' can be described by the crossword solutions of craters (7 letters), bombs (5 letters), and TANKS (5 letters). Craters are large holes in the ground caused by an explosion or impact, such as a bomb or tank. Bombs are explosive devices that cause destruction when detonated, while TANKS are armored military vehicles that are used to attack enemy forces. All three of these solutions indicate a situation in which something has failed miserably.