Double Down

Meaning : To “double down” is to put even more effort into an action once it begins to fail.

(There’s a positive version of “doubling down,” which can describe taking a smart risk. But it’s often used to describe the behavior of someone who’s losing an argument, or who reacts badly to being corrected.)

Sentence : He could have just fixed the mistake. Instead, he doubled down and told me I was the one who was wrong.

Meaning : To “be on board” with something is to be willing to go along with it, or to be enthusiastic about it.

Sentence : I thought we could start our own clothing store. Are you on board?