The most common answer for the crossword clue "Untouchable" is IMMUNE (6 letters), referring to something or someone that cannot be touched or affected, especially in the sense of being immune to disease or attack. Other possible answers depending on context and length include SAFE (4 letters), TOXIC (5 letters), SACRED (6 letters), and SHUNNED (7 letters).
In the context of Indian social classes, "Untouchable" can refer to a member of the lowest social and ritual class, which also fits some crossword clues but is less common as a direct answer unless specified.
For a 6-letter answer, IMMUNE is the best fit for "Untouchable" as a crossword clue.