The Collaborative International Dictionary of English v.0.48:

Neanderthal race \Neanderthal race\, or Neanderthal man
\Neanderthal man\, a species of extinct robust humans, believed
   to have been widespread in the Middle Paleolithic in Europe
   and western Asia; as, a Neanderthal skull.

   Syn: Neanderthalian.
        [Webster 1913 Suppl. + WordNet 1.5]
   2. Similar to or reminiscent of a neanderthal human;
      troglodytic; primitive and uncultured.
      [PJC]

WordNet (r) 3.0 (2006):

Neanderthal man
    n 1: extinct robust human of Middle Paleolithic in Europe and
         western Asia [syn: Neandertal man, Neanderthal man,
         Neandertal, Neanderthal, Homo sapiens
         neanderthalensis]