Case hardened and Hard-boiled

Hard-boiled and case hardened are semantically related. In some cases you can use "Hard-boiled" instead an adjective phrase "Case hardened".

Hard-boiled adjective - Having or showing a lack of sympathy or tender feelings.

Case hardened and hard-boiled are semantically related. Sometimes you can replace phrase "Case hardened" with "Hard-boiled", this phrases are similar.