bulldozer

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A heavy, driver-operated machine for clearing and grading land, usually having continuous treads and a broad hydraulic blade in front.
• noun An overbearing person; a bully.

from The Century Dictionary.

• noun One who bulldozes; one who intimidates others by threats of violence.
• noun A revolver.
• noun A horizontal geared press for bending, shaping, forming, upsetting, and welding heavy bars, rods, and other metal Shapes.

from the GNU version of the Collaborative International Dictionary of English.

• noun Slang One who bulldozes.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun one who bulldozes
• noun usually plural A self-identified group of white US Southerners who colluded to influence outcomes of post-Reconstruction elections by intimidating, coercing and bullying black voters and legislators, including burning down houses and churches, flogging and murdering opponents. Also known as "regulators". Later used to describe anyone who intimidated or bullied in a similar manner.
• noun A tractor with an attached blade for pushing earth and building debris for coarse preliminary surface grading, demolishing building structures, etc.
• noun A bully, overbearing individual.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun large powerful tractor; a large blade in front flattens areas of ground