(transitive, intransitive) To fasten in place or together with (or as if with) a clamp.
1897, Bram Stoker, Dracula Chapter 21As we burst into the room, the Count turned his face, and the hellish look that I had heard described seemed to leap into it. His eyes flamed red with devilish passion. The great nostrils of the white aquiline nose opened wide and quivered at the edge, and the white sharp teeth, behind the full lips of the blood dripping mouth, clamped together like those of a wild beast.
(intransitive) To tread heavily or clumsily; to clump or clomp.