To stew is to slowly cook food, which results in a soup-like food called a stew. To stew also means to brood angrily.
If you cook something slowly, like beef or vegetables, you stew it. The result of stewing is also called stew, which is usually chunky, like a thick soup. People can stew in another way when it comes to emotions. If your sister sits and worries about something, she stews. The root of stew is the Old French estuver, "bathe or stew." Back in the fourteenth century, stew was also a slang word meaning "brothel or bath house."