| desensitized |
| develop(verb, dull, blunt, accustom) |
| discipline(verb, dull, develop, blunt, accustom) |
| disciplined(verb, adjective, calcify, curdled, calloused) |
| disciplining(verb, calcify, curdled, calloused, densify) |
| dulling(verb, calcify, curdled, calloused, densify) |
| embitter(verb, dull, develop, blunt, accustom) |
| firming(verb, calcify, curdled, calloused, densify) |
| fossilize(verb, calcify, curdled, calloused, densify) |
| habituate(verb, dull, develop, blunt, accustom) |
| hard-edged(adjective, stubborn, hardened, toughened, cynical) |
| hard-hearted |
| hard-nosed(adjective, hard, unfeeling, unsympathetic, stubborn) |
| hardboiled(adjective, careless, cruel, apathetic, callous) |
| harden(verb, calcify, curdled, calloused, densify) |
| inexcitable(adjective, callous, unexcitable, hard-as-nails) |
| inhuman |
| inure(verb, dull, develop, blunt, accustom) |
| ironhearted |
| make callous(verb, expression, dull, develop, blunt) |