Anyone who is not surrendering to Krsna, he must be duskrtinah. Duskrtinah means he has got brain, but his brain is being utilized for sinful activities. So duskrtinah, mudhah, and rascal who does not know anything - what is God, what I am, what is this world - he's a rascal. He's animal. Mudhah means ass. As ass does not know what is God, what I am, what is this world, what is our relationship, what is this universe, nothing, no knowledge - mudhah - and duskrtinah, naradhamah means human being is especially meant for understanding this philosophical aspect of life, but one does not care. He is simply acting where to eat, where to sleep and where to get woman, and that's all. That's his business. This is mudhah. This is the business of hogs and dogs.
Lecture on Bhagavad-gita 9.2, Calcutta, 8 March, 1972