Real Dictionary

Malthusian in American English
of Malthus and his theory that the world population tends to increase faster than the food supply with inevitable disastrous results unless natural restrictions, such as war, famine, and disease, reduce the population or the increase is checked by moral r
adjective: of or pertaining to the theories of T. R. Malthus, which state that population tends to increase faster, at a geometrical ratio, than the means of subsistence, which increases at an arithmetical ratio, and that this will result in an inadequate supply of
noun: a follower of Malthus

Malthusian in British English
adjective: of or relating to the theory of Malthus stating that increases in population tend to exceed increases in the means of subsistence and that therefore sexual restraint should be exercised
noun: a supporter of this theory