朝秦暮楚 — “To be fickle, inconsistent, or wavering”

During the Warring States period in ancient China, the seven major states—Qi, Chu, Yan, Han, Zhao, Wei, and Qin—were engaged in intense rivalries. Among these, Qin and Chu were the two most powerful and dominant forces.

Smaller feudal states, for their own survival, security, and interests, often found themselves caught between these two giants. They would align with Qin for a period, seeking protection or advantage, and then, due to shifting circumstances or new opportunities, would switch their allegiance to Chu, only to potentially revert later.

This constant oscillation of loyalties and alliances, like serving Qin in the morning and Chu in the evening, became a metaphor for someone who is fickle, inconsistent, or opportunistic in their choices and loyalties.