- old: to reap the consequences of one's words (idiom, from Mencius); modern: to go back on one's word
- to blow hot and cold
- to contradict oneself
- inconsistent
“go back on one's words; promise and then deny in succession”
尔：你；反：通“返”，回。原意是你怎样做，就会得到怎样的后果。现指人的言行反复无常，前后自相矛盾。
Origin 《孟子·梁惠王下》：“出乎尔者，反乎尔者也。”
Example 倘若不肯，也只好由他，我们不能做～的事。（清·李宝嘉《官场现形记》第五十九回）