忍 (rěn): To endure, tolerate, or bear. The character is a combination of a 'blade' (刃) over a 'heart' (心), vividly picturing the feeling of holding a knife to your heart—it's painful, but you bear it.
辱 (rǔ): To humiliate, insult, or disgrace.
负 (fù): To carry on one's back, to shoulder, to bear a responsibility.
重 (zhòng): Heavy, weighty, serious, or important.
The characters combine literally and powerfully: “To endure (忍) humiliation (辱) while shouldering (负) a heavy (重) burden.” The two parts work together to paint a picture of someone under immense pressure from both external insults and internal responsibility, yet they persevere with a quiet, steely determination.