| stolid(adjective, calm, dull, tough, rational) |
| straight-faced(adjective, dull, dead, impassive, unresponsive) |
| straight face(noun, expression, mask) |
| unaffected(adjective, tough, cold, rational, straightforward) |
| unemotional(adjective, calm, dull, cool, tough) |
| aloof(adjective, blank, unemotional, emotionless, expressionless) |
| autism |
| chill(adjective, cool, flat, detached, blank) |
| cold(adjective, calm, dull, cool, tough) |
| cool cat(expression, adjective, cool, detached, blank) |
| detached(adjective, cool, blank, sober, unfeeling) |
| disinterested(adjective, calm, dull, flat, cold) |
| dispassionate(adjective, calm, dull, cool, flat) |
| dull(adjective, calm, quiet, tough, severe) |
| hard-boiled(adjective, tough, rational, straightforward, detached) |
| imperturbable(adjective, blank, unemotional, emotionless, expressionless) |
| in cold blood(expression, adjective, idiom, cool, flat) |
| lifeless(adjective, calm, dull, tough, flat) |
| matter-of-fact(adjective, calm, cool, rational, straightforward) |
| neutral(adjective, cold, aloof, unexcitable, indefferent) |