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
a fundamental emotional and activating principle determining one's character
any incorporeal supernatural being that can become visible (or audible) to human beings
the vital principle or animating force within living things
the general atmosphere of a place or situation and the effect that it has on people; "the feel of the city excited him"; "a clergyman improved the tone of the meeting"; "it had the smell of treason"