gorilla

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

• noun Either of two large apes (Gorilla gorilla or G. beringei) native to the forests of equatorial Africa, having a stocky body and coarse dark brown or black hair.
• noun A powerfully built, aggressive, and often crude man.
• noun A thug.

from The Century Dictionary.

• noun The largest known anthropoid ape, Troglodytes gorilla, of the family Simiidæ, suborder Anthropoidea, and order Primates, most closely resembling man, especially in the form of the pelvis and in the proportion of the molar teeth to the incisors.
• noun [capitalized] A genus of Simiidæ, having the gorilla, Gorilla gina or G. savagei, as type and only species.

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

• noun (Zoöl.) A large, arboreal, anthropoid ape of West Africa. It is larger than a man, and is remarkable for its massive skeleton and powerful muscles, which give it enormous strength. In some respects its anatomy, more than that of any other ape, except the chimpanzee, resembles that of man.

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

• noun The largest of the apes, native to the forests of central Africa, and known for its trait of knuckle-walking
• noun A big and brutish man or a thug; a goon or ruffian.

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

• noun largest anthropoid ape; terrestrial and vegetarian; of forests of central west Africa