play fast and loose
玩弄花招，不守规矩或不诚实对待某人或某事
口语·指责不守规矩
英文释义
to behave in an irresponsible or unpredictable manner
例句
You can't play fast and loose with the rules and expect to keep your job.
典故来源
源自16世纪一种街头骗局，骗子快速移动绳子让观众猜中圈套，后指行为反复无常、不负责任。