| nonchalant(adjective, calm, quiet, cool, relaxed) |
| thickheaded |
| unflappable(adjective, calm, quiet, cool, indifferent) |
| unintelligent(adjective, dull, simple, slow, foolish) |
| unresponsive(adjective, calm, dull, quiet, flat) |
| cold(adjective, calm, cool, tough, indifferent) |
| controlled(adjective, unexcitable) |
| deadpan(adjective, calm, dull, tough, rational) |
| dry(adjective, calm, dull, cool, tough) |
| dull-witted |
| expressionless(adjective, dull, dead, blank, impassive) |
| foolish(dull, unintelligent, witless) |
| frigid(adjective, calm, unemotional, composed, unexcitable) |
| heavy(adjective, dull, quiet, flat, stupid) |
| placid(adjective, calm, dull, quiet, cool) |
| prosaic(adjective, dull, quiet, tough, flat) |
| shallow(adjective, simple, slow, stupid, sluggish) |
| staid(adjective, indifferent, casual, aloof, sober) |
| supine(adjective, dull, stupid, weary, apathetic) |
| tranquil(adjective, calm, quiet, relaxed, casual) |