Can you explain heterodox economics to me in a succinct way? In class, I am just ...

Well, the simplest way of putting it is that heterodox economics is any kind of economic thought that does not fall into orthodox economic thought. Orthodox economics is usually known as the neoclassical school of economics. Like every other school of economic thought, it is based on certain assumptions about how society works, how human beings work, what the nature of politics is, what the ontology of the market and the state are, how ethics works, etc. These assumptions are dominantly accepted by everyone, especially by those who are part of the Anglophone cultures (including India), that it is hard to imagine economics outside of this school of thought. Heterodox economics is a broad term for all other schools of thought that criticize the assumptions, theories, and policy prescriptions of the neoclassical school. There are numerous schools of thought that can be classified as heterodox. Examples are Austrian, Marxist, Historical, Developmentalist, Institutionalist, Schumpeterian, Socialist, Buddhist, Anarchist, Feminist, Gandhian, Islamic, Georgist, etc. There are many more theories that do not come under any of the above frameworks and schools of thought. The way I've understood heterodox economics is that, above everything else, the predominant criticism of neoclassical economics is its completely ignoring of the political nature of economics. The economy is not an autonomous field with its own laws which cannot and should not be altered. Instead, the market is also a social institution that can be politically structured and can be altered through political action. I believe that it is this understanding that links all heterodox economic thought - economics is not science: it is politics.