Other forms: connivances
If your principal overlooks cheating on standardized tests because it makes his school look better, he is guilty of connivance, or allowing an unethical act to take place.
If your siblings conspire to play a prank on you, you could say they are conniving to trick you. If your mother knew about it, but chose to allow the act to happen, you'd probably be pretty angry at her connivance. Or you could follow the old saying, "Don't get mad, get even!"
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