bruiser

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

• noun A usually large or powerfully built person who is aggressive or readily gets into fights.
• noun A boxer.
• noun A person who enjoys arguing with others.

from The Century Dictionary.

• noun One who bruises.
• noun A concave tool for grinding the specula of telescopes.
• noun The name of various machines for bruising grain, etc., for feeding cattle.
• noun A boxer; a pugilist; a bully.
• noun A name applied to various plants supposed to be efficacious in healing bruises, as bruise-wort, soapwort, etc.

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

• noun One who, or that which, bruises.
• noun A boxer; a pugilist; hence, a strong, tough person; -- often used in the phrase big bruiser.
• noun A concave tool used in grinding lenses or the speculums of telescopes.

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

• noun sports : In contact sports, an athlete whose size, strength, and/or aggressiveness make it likely that he will cause athletes on the opposing team to suffer physical punishment.
• noun By extension, a tall, strong, heavily built man, especially one prone to physical violence.
• noun A thug.

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

• noun a large and strong and heavyset man