"My teacher George is amazing."
Translation:مُعَلِّمي جورْج مُمْتاز.
According to Duolingo, they use أستاذ for "professor". But I have to say this word is also used for teachers in the Arab world, as well sometimes using it for elders or for professionals. The word أستاذ is the origin for the Spanish "Usted".
The word معلم (mu3allim) is teacher in general. Beside that, also in the dialects they use this word like the previous one (specially for someone professional)... it is pretty common term in Egypt.