The Greek katakurieuō (G2634) means to lord it over, to exercise dominion, or to master completely. The prefix kata intensifies: it is domineering lordship. Jesus uses it in defining the contrast between worldly and servant leadership: 'You know that the rulers of the Gentiles lord it over (katakurieuō) them, and their high officials exercise authority over them. Not so with you' (Matthew 20:25-26). Peter uses the same word to warn elders: 'Not lording it over (katakurieuō) those entrusted to you' (1 Peter 5:3).
Katakurieuō is the negative pole against which Christian leadership is defined. The world's leadership model is domination — using power to control others, to secure one's position, to extract service from subordinates. Jesus explicitly forbids this in the church: the greatest must be servant of all, following the pattern of the Son of Man who 'came not to be served, but to serve, and to give his life as a ransom for many' (Matthew 20:28). Peter's echo of this in 1 Peter 5:3 adds: the alternative to katakurieuō is being an example to the flock — servant leadership visible in incarnate life.