形容詞 fickle:

1. marked by erratic changeableness in affections or attachments
   同義詞：volatile
2. liable to sudden unpredictable change
   同義詞：erratic, mercurial, quicksilver

1. It's the third time that he changed his mind; he's so fickle!
   ＂他改變主意已經(jīng)是第三回了，他這人太反復(fù)無(wú)常了?。?/div>
2. Fortune's fickle wheel.
   多變的命運(yùn)之輪。
3. He turned out to be fickle - he has left me.
   他原來(lái)是個(gè)善變的人 - 他離開我了。

fick.le

adj.（形容詞）
Characterized by erratic changeableness or instability, especially with regard to affections or attachments; capricious.
無(wú)常的，易變的：表現(xiàn)為無(wú)規(guī)律的變化或者不穩(wěn)定性的，尤指在感情或愛(ài)慕方面；反復(fù)無(wú)常的

來(lái)源：
Middle English fikel
中古英語(yǔ) fikel
from Old English ficol [deceitful]
源自 古英語(yǔ) ficol [欺騙的]

【引伸】
fick.leness
n.（名詞）
fick.ly
adv.（副詞）