case hardened

/keɪs ˈhɑrdənd/
adjective
  1. Made emotionally tough or insensitive by difficult experiences.
    • Years of working in the emergency room left her case-hardened to blood and injuries.
    • The reporter was case-hardened to the sad stories she heard every day.
    • He became case-hardened after being cheated by several business partners.
  2. Describing metal that has been given a hard outer surface while remaining softer inside, usually through a heat treatment process.
    • Case-hardened tools last longer because the surface resists scratches.
    • The sword was case-hardened to make the blade tough but not brittle.
    • The mechanic used case-hardened steel for the gears to reduce wear.
What does "case hardened" mean? | whatsthatwordmean | whatsthatwordmean