1610s, from Portuguese paria or directly from Tamil paraiyar, plural of paraiyan "drummer" (at festivals, the hereditary duty of members of the largest of the lower castes of southern India), from parai "large festival drum." "Especially numerous at Madras, where its members supplied most of the domestics in European service" [OED]. Applied by Hindus and Europeans to any members of low Hindu castes and even to outcastes. Extended meaning "social outcast" is first attested 1819.