Euarestos means 'well-pleasing' or 'acceptable' — that which finds favor and approval. Combining eu (good, well) with arestos (pleasing, agreeable), it describes actions, attitudes, or persons that are genuinely pleasing and acceptable. It is most powerfully used in Romans 12:1-2 to describe the 'living sacrifice' as 'holy and pleasing [euarestos] to God.'
Romans 12:1 contains one of Paul's most comprehensive calls to discipleship: presenting our bodies as living sacrifices that are 'holy, and pleasing [euarestos] to God.' This is 'true and proper worship.' The entire ethical section of Romans flows from this single goal: living in a way that is acceptable to God. Philippians 4:18 uses the same word for the gift the Philippians sent — 'an acceptable sacrifice, pleasing to God.' The theology is that worship is not only liturgical but totalistic: every act of self-giving, every sacrifice of comfort or resources, is worship when offered to God as euarestos.