1. Incapable of being mitigated
   "stern and unmitigable accusations"

See also: implacable

• irreligious
• irreligiousness
• irremediable
• irremediably
• irremissible
• irremovable
• irreparable
• irreparably
• irreplaceable
• irreplaceableness
• irrepressibility
• irrepressible
• irrepressibly
• irreproachable
• irreproachably
• irreproducibility
• irreproducible
• irresistibility
• irresistible
• irresistible impulse
• irresistibleness
• irresistibly
• irresolute
• irresolutely
• irresoluteness