A Widerspruch (objection) is a legal remedy you can use to challenge certain decisions made by public authorities.
If you do not agree with a decision made by a public authority, you can file an objection and explain why you think the decision is wrong. The public authority will then review the decision again. You can only file an objection if this is allowed for the decision.
For example, you can file an objection if your application for Sozialleistungen (social benefits) was denied or if you receive less money than you expected.