Peronism simply put is the cancer that holds Argentina back.
It is the make work nature of AFIP/Aduana, the nepotism of Aerolineas and The Campora, the "with us or against Argentina" approach of the government, and many more ills to boot.
It presents itself as a populist, socially liberal, economically statist idealogy when in practice it has been an authoritarian mismanaged neoliberal neptocratic mess where the people get screwed and oppressed, and the leaders, members of congress, senators, governors and Peronjugend allies prosper with government largesse and cronyism.
But I degress, for a clear definition of what Peronism is, the best answer maybe what its not: a well thought out way to run a country. Just ask Argentina's neighbors if they believe in it.