untouchable
adjective
[ ʌnˈtʌtʃəb(ə)l ]
• not able or allowed to be touched or affected.
• "drug barons who were legally untouchable"
• of or belonging to the lowest-caste Hindu group or the people outside the caste system.
untouchable
noun
• a member of the lowest-caste Hindu group or a person outside the caste system, contact with whom is traditionally held to defile members of higher castes.