Main entry: hardness, ruggedness
Definition: the quality of being difficult to do
Usage: he assigned a series of problems of increasing hardness; the ruggedness of his exams caused half the class to fail
Main entry: ruggedness
Definition: the quality of being topologically uneven
Usage: the ruggedness of the mountains
Main entry: huskiness, toughness, ruggedness
Definition: the property of being big and strong