反复无常

反复无常 [fǎn fù wú cháng]

1. ■ play fast [at fast] and loose; be unsteady; blow hot and cold; change like a weathercock; change one's mind constantly; change one's mind frequently; (He) is always chopping and changing.; repeatedly to change one's attitude towards:

反复无常天气 fickle weather;

反复无常的情绪 fickle moods;

反复无常的人 inconstant sort of fellow; chameleon;

这个人反复无常， 很不可靠。 This fellow is always chopping and changing; he's very unreliable.