| immutable(adjective, dull, steady, stable, regular) |
| impartial(adjective, calm, detached, sober, unfeeling) |
| impersonal(adjective, calm, detached, sober, unfeeling) |
| in control(expression, adjective, tranquil, unperturbed) |
| in equilibrium |
| inactive(adjective, quiet, cool, indifferent, still) |
| indurated(adjective, cool, blank, aloof, unemotional) |
| inert(adjective, quiet, indifferent, apathetic, lifeless) |
| inexpressive(adjective, cool, blank, aloof, unemotional) |
| inirritable |
| insensible(adjective, cool, blank, aloof, unemotional) |
| insusceptible(adjective, cool, blank, aloof, unemotional) |
| intent(adjective, firm, determined, usual, regular) |
| invariable(adjective, dull, steady, stable, regular) |
| inveterate(adjective, firm, determined, usual, regular) |
| ironclad(adjective, firm, determined, usual, regular) |
| judicial(adjective, calm, detached, sober, unfeeling) |
| just(adjective, calm, detached, sober, unfeeling) |
| keeping a stiff upper lip(expression, adjective, idiom, calm, relaxed) |
| laid back(expression, adjective, calm, cool, relaxed) |