ADJECTIVE (3)

1. not responding to some influence or stimulus;

2. aloof or indifferent;
- Example: "was unresponsive to her passionate advances"

3. not susceptible to suggestion or influence;

WordNet (r) 3.0 (2006):

unresponsive
    adj 1: not responding to some influence or stimulus [ant:
           responsive]
    2: aloof or indifferent; "was unresponsive to her passionate
       advances"
    3: not susceptible to suggestion or influence

Moby Thesaurus II by Grady Ward, 1.0:

81 Moby Thesaurus words for "unresponsive":
   affectless, anesthetized, arctic, autistic, blunt, callous,
   calloused, catatonic, chill, chilly, closed to, cold,
   cold as charity, cold of heart, cold-blooded, coldblooded,
   coldhearted, cool, dispassionate, drugged, dull, emotionally dead,
   emotionless, flinthearted, frigid, frosted, frosty, frozen, hard,
   hard of heart, hardened, hardhearted, heartless, icy, immovable,
   impassible, impassive, impersuadable, impersuasible, impervious,
   inexcitable, inflexible, inhibited, insensitive, insentient,
   insusceptible, nonemotional, obdurate, objective, obstinate,
   obtuse, out of touch, passionless, self-absorbed, soulless,
   spiritless, stonyhearted, unaffectionate, unamenable, undersexed,
   unemotional, unfeeling, unimpassioned, unimpressible,
   unimpressionable, uninfluenceable, unloving, unmerciful, unmovable,
   unnatural, unpassionate, unpersuadable, unpliable, unreceptive,
   unresponding, unsuggestible, unsusceptible, unswayable,
   unsympathetic, untouchable, unyielding