| impercipient |
| impersonal(adjective, cool, detached, blank, sober) |
| implacable(adjective, mean, hard, tough, harsh) |
| in cold blood(expression, adjective, idiom, cool, detached) |
| inaccessible(adjective, hard, unfeeling, unsympathetic, hardened) |
| inanimate(adjective, hard, tough, severe, cruel) |
| incurious(adjective, hard, indifferent, detached, weary) |
| inexorable(adjective, mean, hard, tough, harsh) |
| inflexible(adjective, mean, hard, careless, indifferent) |
| innate |
| insusceptible(adjective, hard, insensitive, unsusceptible) |
| iron(adjective, mean, hard, tough, harsh) |
| iron-hearted(adjective, hard, tough, severe, cruel) |
| laid-back(adjective, calm, restrained, detached, unconcerned) |
| laid back(expression, adjective, cool, indifferent, detached) |
| larger-than-life |
| lion |
| listless(adjective, indifferent, detached, weary, apathetic) |
| lone wolf(expression, adjective, indifferent, detached, distant) |
| loner(adjective, indifferent, detached, distant, remote) |