Iain Murray, Evangelicalism Divided:

Worldliness is departing from God.  It is a man-centered way of thinking.  It proposes objectives which demand no radical breach with man’s fallen nature.  It judges the importance of things by the present and material results.  It weighs success by numbers.  Worldliness covets human esteem and wants no unpopularity.  It knows no truth for which it is worth suffering.  It declines to be a fool for Christ’s sake.  Worldliness is the mindset of the unregenerate.  It adopts idols and it is at war with God.”

(HT:  C. J. Mahaney)