have something/anything to say for (oneself)
1. To be able to explain or defend one's actions. I told you not to throw the ball in the house, and now, the vase is broken. Do you have anything to say for yourself?
2. To be able to converse with others. That guy is a real dullard—he doesn't have anything to say for himself.
have something (or nothing) to say for yourself
contribute (or fail to contribute) to a conversation or discussion.