无常的英文：
variable
changeable
fickle
impermanence
ghost supposed to take a soul upon death
to pass away
to die

参考例句：

The affairs of the world are inconstant
世事无常

Life is changeable.
世事无常。

Life is inconstant, evanescent
性命无常

Parting and meeting are irregular
散聚无常

A sage has more than one teacher.
圣人无常师。

The popularity of the film stars waxed and waned.
电影明星们的名望盛衰无常。

Modern character is inconstant, divided, vacillating
现代人的个性是无常的，分裂的，摇摆不定的。

And every fair from fair sometime declines
被机缘或无常的天道所摧折，

His relations with me were subject to spasmodic outbursts tending constantly to get worse
他跟我的关系由于冷热无常而每况愈下。

Life is a dream a little less inconstant
人生是一场稍稍不那么无常的梦而已。

variable是什么意思：
n. 可变的事物，可变的量
adj. 可变的，不定的；亮度变化的

The frequency inverters has a function of variable voltage and variable frequency.
频率逆变器具有变压、变频功能。

mode of random variables
随机变量的众数

subscript variable symbo
下标变量符号

changeable是什么意思：
adj. 无常的，易变的

changeable behavior.
可改变的行为

Life is changeable.
世事无常。

The forecast is for changeable weather.
预报针对的是变化无常的天气。

fickle是什么意思：
adj. 易变的，无常的；浮躁的

Fluctuating prices usually base on a fickle public's demand.
物价的波动往往是由于群众需求的不稳定而引起的。

feeling of doubt, fickleness uncertainty, and fear of loss often accompany infatuation.
疑虑，花心，不确定和对失落的恐惧常与迷恋如影随形。

As for independents wavering most, unattached voters are naturally more fickle than loyalists.
至于波动最大的独立选民，他们本来就比忠诚的支持者易变。