1. 平稳：placid 平静的 | placidity 平稳 | placidly 平稳地

2. 平稳/平静/温和：placid /平稳的/平静的/沈著的/满足的/澹/ | placidity /平稳/平静/温和/ | placidly /平稳地/宁静地/沉着地/

3. 平稳; 温和; 沉着 (名)：placid 平静的, 平稳的, 沉著的 (形) | placidity 平稳; 温和; 沉着 (名) | placidness 平静 (名)

noun

1. a disposition free from stress or emotion

Synonym: reposequietserenitytranquillitytranquility

2. a feeling of calmness
a quiet and undisturbed feeling

Synonym: placidness