详细解释:n. 坚硬, 困难, 严厉, 勇气
【化】 硬度
【医】 硬度, 硬性
英语解释：
名词 hardness:
the property of being rigid and resistant to pressure; not easily scratched; measured on Mohs scaledevoid of passion or feeling; hardheartedness同义词：unfeelingness, callousness, callosity, insensibility