niえるeru
1.

To undergo a process where heat causes raw ingredients to become tender and suitable for consumption, such as a vegetable softening in boiling water.

2.

To reach a state where a liquid is heated to the point of bubbling, transforming from a cold or solid state into a hot, often fluid state, as seen with water becoming hot or asphalt softening under heat.

3.

To experience intense emotional agitation, particularly when one feels a strong sense of frustration or irritation.

4.

To come to a resolution or agreement during discussions, indicating a situation where dialogue leads to a conclusion.

5.

To create a chaotic or noisy atmosphere, often in response to a significant event, suggesting a scene of disruption or commotion.

Example:

スープがなべでぐつぐつ煮えている。