反复无常的英文：
[Literal Meaning]
repeat/no/stability
always changing and not stable

[解释]
经常变化，不稳定。

[Explanation]
capricious

[例子]
最近天气反复无常，你要多注意增减衣服。

[Example]
Recently the weather is always changing and you'd better be aware of your dressing.

[英语等价词]
to play fast and loose

Swayed or prompted by caprice;unpredictable.
难以捉摸的或反复无常的;无法预言的

He has a volatile temper.
他脾气反复无常。

She is versatile.
她反复无常。

wanton destruction.
反复无常的毁坏

To be capricious;trifle.
做事反复无常;浪费

Woman's a various and a changeful thing
女人是反复无常，变化多端的。

An erratic mind jump from one idea to another.
心意不定的人反复无常。

You are inconsistent and unpredictable.
你这人反复无常，真叫人难以捉摸。

The old man had always been cranky and erratic.
那老头儿性情古怪，反复无常。

A capricious liking or inclination.
一时的爱好反复无常的爱好或倾向