1.  ruggedness(n = noun.attribute) huskiness, toughness - the property of being big and strong;
is a kind of strength
Derived form adjective rugged₁

2.  ruggedness(n = noun.attribute) - the quality of being topologically uneven; "the ruggedness of the mountains"
is a kind of unevenness, variability
has particulars: hilliness
Derived form adjective rugged₃

3.  ruggedness(n = noun.attribute) hardness - the quality of being difficult to do; "he assigned a series of problems of increasing hardness"; "the ruggedness of his exams caused half the class to fail"
is a kind of difficultness, difficulty
Derived form adjective rugged₄