adjective (clarification of this definition is needed)(The addition of quotations indicative of this usage is being sought:) Holding one's own self-interest as the standard for decision making.
adjective Having excessive or exclusive regard and concern for one's own well-being, profit or pleasure, with little or no consideration for others.
adjective Of video game characters: relying on their own actions and capabilities to be effective in the game, rather than on other characters.
adjective Related to or equivalent to a selfish gene; best understood as existing to preserve and replicate itself in competition with other entities at the same level of existence, rather than at the level of the individual or population containing it.