lock horns

Fig. to get into an argument with someone. Let's settle this peacefully. I don't want to lock horns with the boss. The boss doesn't want to lock horns either.

to argue with someone in a very determined way In her new movie she plays a middle-aged college student who locks horns with her professor.

if two people lock horns, they argue about something (often + over ) The mayor and her deputy locked horns over the plans for the new road.

Become embroiled in conflict, as in At the town meeting Kate and Steve locked horns over increasing the property tax. This expression alludes to how stags and bulls use their horns to fight one another. [First half of 1800s]

To become embroiled in conflict.

To get into an argument. Two deer, moose, or members of another antlered species who have a dispute they want to settle will face off, paw the ground, and charge at each other. Their antlers clash and often become enmeshed. They have locked horns. People who have a bone to pick can be said to lock horns too. The phrase appears in an 1865 poem by Algernon Swinburne to describe the domestic disagreement of a heifer and her mate locking horns.