Good will (2133) (eunoia from eunoéo = to favor, be well disposed, meet halfway <> eú = well + noús = mind) describes a positive attitude exhibited in a relationship, a good attitude, a wholehearted zeal or a willingness. Eunoia describes an eagerness that does not wait to be compelled. It was a common term in diplomatic documents in referring to positive attitudes displayed by a person, city, or state. In this verse the admonition that slaves should serve with eunoia corresponds to a general view of antiquity but is given a new basis, namely, that the service is now rendered to the Lord. This is the only NT use except for one use in Textus Receptus rendering of 1Cor 7:3... Let the husband render unto the wife due benevolence: and likewise also the wife unto the husband. (euphemistic for conjugal relations) Webster says goodwill is a kindly or feeling of approval and support. It is benevolent interest or concern. Eunoia means we serve not just with readiness but with the disposition that wishes one well. Expositor's Bible Commentary writes that... Among the Oxyrhynchus papyri there is a will dated A.D. 157 in which the testator freed five slaves "because of their good-will and affection" (III. No. 494, lines 5, 6). If even pagan slaves could display such qualities, how much more should Christians do so, without expecting manumission as a reward. (Gaebelein, F, Editor: Expositor's Bible Commentary 6-Volume New Testament. Zondervan Publishing)