| nonchalant(adjective, calm, cool, relaxed, casual) |
| obdurate(adjective, cold, indifferent, stiff, inflexible) |
| obstinate(adjective, mean, hard, harsh, inflexible) |
| passionless(adjective, cool, blank, aloof, unemotional) |
| perverse(adjective, mean, hard, tough, harsh) |
| phlegmatic(adjective, cool, blank, aloof, unemotional) |
| pigheaded(adjective, mean, hard, harsh, inflexible) |
| placid(adjective, calm, cool, relaxed, casual) |
| poker-faced(adjective, cool, blank, aloof, unemotional) |
| relentless(adjective, mean, hard, tough, harsh) |
| reserved(adjective, cool, blank, aloof, unemotional) |
| reticent(adjective, cool, blank, aloof, unemotional) |
| rigid(adjective, mean, hard, harsh, inflexible) |
| sedate(adjective, cool, blank, aloof, unemotional) |
| self-contained(adjective, cool, blank, aloof, unemotional) |
| serene(adjective, calm, cool, relaxed, casual) |
| set in stone(expression, adjective, idiom, mean, hard) |
| smooth(adjective, calm, cool, relaxed, detached) |
| spiritless(adjective, cool, blank, aloof, unemotional) |
| stiff-necked(adjective, mean, hard, tough, harsh) |