to strike or push with the head or horns.

to strike or push something or at something with the head or horns.

to project.

Machinery . (of wheels in a gear train) to strike one another instead of meshing.

a push or blow with the head or horns. ?

butt in, to meddle in the affairs or intrude in the conversation of others; interfere

It was none of his concern, so he didn't butt in.

butt out, to stop meddling in the affairs or intruding in the conversation of others

Nobody asked her opinion, so she butted out.

verb

barge in , bother , burst in , charge in , chisel in , cut in , disturb , get into the act , interject , interrupt , intrude , muscle in , pester , poke one’s face in , pry , put one’s two cents in , horn in , interfere , interlope