[fǎn fù wú cháng]
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
fickle weather
反复无常天气
fickle moods
反复无常的情绪
inconstant sort of fellow; chameleon
反复无常的人
This fellow is always chopping and changing; he's very unreliable.
这个人反复无常， 很不可靠。