Lacking consideration for others; concerned chiefly with one's own personal profit or pleasure. His selfish behavior made it difficult for others to work with him.
Characteristic of a gene, organism, or system that appears to promote its own survival or advantage at the expense of others. In evolutionary theory, a "selfish gene" propagates itself even when doing so does not benefit the species as a whole.
(Biology, genetics) Of a genetic element: tending to replicate or spread within a genome regardless of its effect on the fitness of the organism. Selfish genetic elements can outcompete neutral ones even if they harm the host organism.