simmer

1. To cook or undergo heating slowly at or below the boiling point. (intransitive) · The soup simmered on the stove.
2. To cause to cook or to cause to undergo heating slowly at or below the boiling point. (transitive) · Simmer the soup for five minutes, then serve.
3. To be on the point of breaking out into anger; to be agitated. (figuratively, intransitive)
4. To remain angry with someone or something past the point of exhaustion; to resign oneself to holding a grudge, especially after some failed attempts to resolve a situation. (figuratively, intransitive) · I tried to get through to him; all that's left for me to do is simmer.
5. To develop gradually, of an idea or plan. (figuratively, intransitive)

He/she/it simmers · Past simmered · Past participle simmered · -ing form simmering