Meaning: In collusion or working closely together.

Explanation:
The phrase "hand in glove" refers to two or more people who are working together closely, often in a secretive or dishonest way, to achieve a common goal. The phrase suggests a relationship where the parties are inextricably linked, like a hand in a glove, and cannot function effectively without each other. It is often used to describe a situation where two people are working together for their mutual benefit, even if their actions are not entirely ethical.

For example, imagine two business partners who are engaged in a fraudulent scheme to defraud their clients. They work together closely, sharing information and coordinating their efforts to cover up their illegal activities. In this case, we might say that they are "hand in glove" with each other.

In another example, two political rivals might be working together secretly to undermine a common enemy. They may disagree on many issues, but they recognize that they can achieve their goals more effectively by working together. In this case, we might also say that they are "hand in glove" with each other.

Overall, the phrase "hand in glove" suggests a close and often secretive working relationship between two or more people who are working together to achieve a common goal, even if their actions are not entirely ethical or above board.