Right, so Selfish people is the definition, pointing us to egoists. For the wordplay, "say" gives you EG (as in "for example"), "Oscar" is O in the NATO phonetic alphabet, "is" just gives you IS straight, and "extremely tedious" means you take the outer letters of "tedious" to get TS. String those together — EG, O, IS, TS — and you've got your answer.