unsusceptible (adj.)

• arctic
• autistic
• blunt
• catatonic
• changeless
• chilly
• cold
• cold-blooded
• coldhearted
• constant
• cool
• dispassionate
• drugged
• dull
• emotionless
• frigid
• frosted
• frosty
• frozen
• heartless
• icy
• immovable
• immutable
• impassive
• impervious
• incommutable
• inconvertible
• indefeasible
• inert
• inflexible
• insensitive
• insentient
• insusceptible
• invariable
• irretrievable
• irreversible
• irrevocable
• lasting
• noble
• nonreturnable
• nonreversible
• objective
• obstinate
• obtuse
• passionless
• permanent
• self-absorbed
• soulless
• spiritless
• unaffectionate
• unalterable
• unaltered
• unchangeable
• unchanged
• unchanging
• undeviating
• unemotional
• unfeeling
• unimpassioned
• unimpressionable
• unloving
• unmodifiable
• unmovable
• unpersuadable
• unreceptive
• unremitting
• unresponsive
• unsympathetic
• untouchable
• unvarying
• unyielding