大乘起信論義記 3.62

3.62

前三染心俱名為麁，於中初執相應染復更為麁，故云麁中之麁也。三賢位名內凡，能覺此染，故云凡夫境界。

The former three defiled minds are all named coarse; among them, the first, attachment-conjoined defilement, is even coarser, hence it is called 'the coarsest among the coarse'. Those in the ranks of the three worthies are called inner ordinary persons; they can become aware of this defilement, hence it is called 'the realm of ordinary persons'.