What does the word “masters” denote?

The specific term Peter uses here is not the usual word for master, but one that describes the master as having total control over his slaves (be it without any negative inferences; see Luke 2:29; Acts 4:24; Revelation 6:10 where the same word is used of God). Given, however, that a human master is a sinner, and the household slave is frequently in his/her face, the opportunity for abuse (whether verbal or otherwise) is constantly real. Mrs. Potiphar’s approach to Joseph in Genesis 39:7 provides a vivid example.