selfish (adj.) Look up selfish at Dictionary.com
1630s, from self + -ish. Said in Hacket's life of Archbishop Williams (1693) to have been coined by Presbyterians. In the 17c., synonyms included self-seeking (1620s), self-ended and self-ful.
Let us understand what our own selfish genes are up to, because we may then at least have the chance to upset their designs. [Richard Dawkins, "The Selfish Gene," 1976]
Related: Selfishly; selfishness.