Definition: to concede a point, or to become less assertive.
(This phrasal verb has more than one meaning.)
E.g.1: He’s so aggressive! When you argue with him he won’t back down until you admit he’s right – even when he’s clearly wrong!
E.g.2: I think he’ll back down over suing the company if we apologize and offer to pay his costs.
This phrasal verb cannot be separated (E.g.1 and 2)