| What is the Indo-Iranian etymology you are proposing? There is no attested word "achaara" referring to a pickle in any Sanskrit dictionary I know of (I just checked several). The standard Sanskrit words for pickle have very clear analyses, i.e. avaleha ("licked down"). A similar analysis of "achaara" in Sanskrit would lead to a nonsense meaning of "not-moving". Whereas, there is a clearly related Persian word "achaar" for a similarly preserved food, which apparently doesn't appear in any Indian texts prior to Mughal rule of South Asia. Even if there were a shared Avestan/Sanskrit antecedent, many words that share a common ancestor in those languages got re-borrowed in their Persian form into Hindi during Mughal rule. For example, the common Hindi word "garam", meaning hot, is a direct borrowing from Persian "garm". It replaced a related word for hot/heat from Sanskrit: "gharma" (the loss of original aspiration on the "g" is a feature of Persian). Both words share the same origin, but the Persian version is the one used across South Asia today. Similarly, Hindi "chaador" meaning "blanket", is a Persian borrowing that also has a Sanskrit cognate "chhaadana" meaning "cover". |
I couldn't find the etymology for achar, but I found references to classical Persian (Avestan) and Proto-Indo-Iranian. Apparently Ayurveda mentions achar, so it's possible that at some point there was a distinction between medicinal pickles and popular everyday pickles.
Nobody knows of course, but to me it's likely that achar has ancient origins, possibly in old Indus Valley or Gangetic Plains. In either case, history of pickle in Indian subcontinent and words used to describe isn't as simple as a loan word.