The mirasi was the village genealogist and musician: a Muslim hereditary performer attached to particular families, who kept and recited their lineages at weddings and other occasions, played the dhol, sang, and was paid in grain and gifts.
The word comes from mirath, inheritance, because what he held was the family's inheritance of names.
A mirasi could recite a household's descent for many generations and it was his professional standing to be accurate. That was the genealogical record of a largely unlettered society and it was oral.
In 1947 the mirasis left Indian Punjab almost entirely, with the rest of the Muslim population. The families they served kept the land and lost the record.
What that removed from the villages of Indian Punjab has never been assessed. A very large number of Punjabi families cannot trace themselves past three or four generations and the reason is that the man who could was in Pakistan by October 1947.
In Pakistani Punjab the mirasi tradition continues in reduced form, and the word has also become a term of contempt.
The mirasi held the family's genealogy in memory, sang it at weddings and at funerals, and was paid by the families whose record he kept.
They were Muslim and almost all of them went to Pakistan in 1947. What went with them was the oral genealogical record of most Punjabi families.
The word is used as an insult now in Punjabi. A community that carried the memory of everybody else's ancestors is remembered mainly in a slur.