lock horns (with somebody) (over something)idiomPart ofhornlock horns (with somebody) (over something)lock horns (with somebody) (over something) — idiomidiom1. To start arguing or fighting with someone about something.1.idiomDefinitionTo start arguing or fighting with someone about something.ExampleThe two politicians locked horns over the new tax proposal.Sara locked horns with her neighbor about the noisy dog.