一味异想天开的英文：
indulge in the wildest fantasy

参考例句：

Indulge in the wildest fantasy
一味异想天开

indulge是什么意思：
v. 使高兴；满足；纵容；（使）沉迷于

You are too indulgent with your children.
你太放纵孩子了。

They indulge in tall talk.
他们一味说大话。

Their foibles were treated with indulgence.
大家以宽容的态度对待他们的那些小缺点。

wildest是什么意思：
[ wild ]的形容词最高级

In his wildest abandon, he indulged himself in alcohol.
在他最狂野的放纵中，他无尽地畅饮。

…he had not the least command over any of his passions: and that which had at any time the ascendant in his mind, hurried him to the wildest excesses
他完全不会克制喜怒哀乐之情，只要一阵心血来潮，他立刻就若醉若狂毫无节制。

fantasy是什么意思：
n. 幻想；空想的产物；幻觉
v. 想像，幻想；奏幻想曲
adj. 虚幻的

Her recollection seems to be a fantasy.
她的回忆似乎只是一种一厢情愿的幻觉。

I no longer fantasy that.
我不再幻想那个了。

George lives in a world of fantasy.
乔治整天生活在幻想的世界中。