这是一个非常圆滑的回答。

That's a very ___diplomatic answer.

我们可能必须圆滑老练，但也必须诚实坚定。

We may have to be ___diplomatic and tactful, but we also must be honest and firm.

他圆滑地处理了冲突，避免了一场重大危机。

His ___diplomatic handling of the conflict prevented a major crisis.