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
the quality of not putting yourself first but being willing to give your time or money or effort etc. for others; "rural people show more devotion and unselfishness than do their urban cousins"
away from the outer edge; "an inner lane"; "the inside lane"
relating to or being on the side closer to the center or within a defined space; "he reached into his inside jacket pocket"; "inside out"; "an inside pitch is between home plate and the batter"
confined to an exclusive group; "privy to inner knowledge"; "inside information"; "privileged information"