the word "untouchable" is a modern english formation built from three distinct elements. the core, "touch", entered english from old french, tracing back to a vulgar latin verb related to striking or making contact. the prefix "un-", of ancient germanic origin, is a prolific negator, reversing the meaning of the base it attaches to. the suffix "-able", of latin descent via french, converts verbs into adjectives meaning "susceptible to" the action. therefore, the literal construction "not capable of being touched" evolved from its primary physical sense to encompass social and metaphorical dimensions, most notably describing a person considered ritually polluting in the hindu caste system, and later, someone or something beyond reach or criticism.

Structure: un (not) + touch (to feel with the hand) + able (capable of) un: a prefix of germanic origin, meaning "not" or "opposite of". touch: from old french 'tochier', ultimately from a vulgar latin base meaning "to knock, strike", indicating physical contact. able: a suffix from latin '-abilis', meaning "capable of, fit for, tending to".