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to get complicated; to grow worse; to turn sour
問題がこじれて解決が難しくなってしまった。
The problem got complicated and became hard to solve.
人間関係がこじれると修復するのは大変だ。
When relationships get complicated, it's hard to repair them.
早く謝らないと話がこじれることになるよ。
If you don't apologize soon, things will get complicated.