the quality of being not particularly suitable or befitting; "he retracted nothing that he had said about the inappropriateness of either a corporeal God or a God who is a person"; "his praise released from her loud protestations of her unworthiness"
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"
the property of being rigid and resistant to pressure; not easily scratched; measured on Mohs scale