Nadhr or Nadhir (English: one who warns) is an Arabic word that refers to prophets.
إِنَّا أَرْسَلْنَاكَ بِالْحَقِّ بَشِيرًا وَنَذِيرًا وَلاَ تُسْأَلُ عَنْ أَصْحَابِ الْجَحِيمِ
Verily, We have sent thee [Muhammad] with the truth, as a bearer of glad tidings and a warner: and thou shalt not be held accountable for those who are destined for the blazing fire.—Quran, Chapter 2, verse 119