a. protected against attack (especially by nuclear weapons)
s. converted to solid form (as concrete)
a. 变硬的；坚定的
1. The hardened criminal was sentenced to ten years in prison.
这个顽固不化的罪犯被判处十年监禁。
2. After years of exposure to the sun, the plastic has become hardened and brittle.
经过多年的阳光照射，塑料变得坚硬且易碎。
3. She tried to soften her hardened heart after the painful breakup.
她试图在痛苦的分手后软化自己那颗坚硬的心。