"calm" 的反义词是 storm。

"calm" 是一个形容词，意思是平静、镇静。它的反义词 "storm" 意味着风暴、混乱。这两个词在含义上是相对的，因此 "calm" 的反义词可以用来表达一种强烈、混乱、狂暴的状态。

例如：

The sea was calm during the night, but a storm was brewing on the horizon.（夜晚海面平静，但地平线上酝酿着一场风暴。）

She felt calm and composed after her conversation with the counselor.（在与顾问谈话后，她感到平静和镇定。）