The Collaborative International Dictionary of English v.0.48:

Malthus \Malthus\ prop. n.
   Thomas Robert Malthus, an English economist who argued that
   increases in population would outgrow increases in the means
   of subsistence (1766-1834).

   Syn: Thomas Malthus, Thomas Robert Malthus.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Malthus
    n 1: an English economist who argued that increases in
         population would outgrow increases in the means of
         subsistence (1766-1834) [syn: Malthus, Thomas Malthus,
         Thomas Robert Malthus]