The Collaborative International Dictionary of English v.0.48:

Chimpanzee \Chim*pan"zee\ (ch[i^]m*p[a^]n"z[-e]; 277), n. [From
   the native name: cf. F. chimpanz['e], chimpans['e],
   chimpanz['e]e.] (Zool.)
   An african ape (Pan troglodytes, formerly Anthropithecus
   troglodytes, or Troglodytes niger) which approaches more
   nearly to man, in most respects, than any other ape. It is
   the most intelligent of non-human animals, and when full
   grown, it is from three to four feet high. A variant called
   the pygmy chimpanzee, or bonobo, has been recently
   recognized as a separate species.
   [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

chimpanzee
    n 1: intelligent somewhat arboreal ape of equatorial African
         forests [syn: chimpanzee, chimp, Pan troglodytes]

Moby Thesaurus II by Grady Ward, 1.0:

29 Moby Thesaurus words for "chimpanzee":
   Cape polecat, ape, bar, bear, cavy, chimp, coon, ferret, foumart,
   glutton, groundhog, guinea pig, hedgehog, monk, monkey, mousehound,
   opossum, polecat, porcupine, possum, prairie dog, quill pig,
   raccoon, skunk, weasel, whistle-pig, wolverine, woodchuck, zoril