أستاذ (ustaad) — "professor" in Modern Standard Arabic

adraka ad-duktur nabil ustadh at-tarikh al-baligh min al-umr ithnayn wa-arba'in aaman bi-khawfin shadidin anna al-mawid an-niha'iy li-daf'i rusum an-nashri qad halla wa-mahfazatahu farighatun tamaman.

Dr. Nabil, a forty-two-year-old history professor, realized with extreme fear that the final deadline to pay the publishing fees had arrived, and his wallet was completely empty.

from A Race Against Time in Downtown

Thumma iqtaraba al-ustādh Ḥasan, zamīluhā, māddan yadahu bi-ḥarārah: "Ṣabāḥ al-khayr yā Layla, hal anti dhāhibatun ilā ijtima' al-wafdi al-yābānī?"

Then Professor Hassan, her colleague, approached, extending his hand warmly: "Good morning, Layla, are you going to the Japanese delegation meeting?"

from The Urgent Greeting: Layla at the National Museum

Ahlan bika ya Ustadh Amin.

Welcome, Professor Amin.

from Morning Greetings at the Library

Sabah al-khayr, ustadh duktur Kamal, atamanna an takunu bi-khayrin al-yawm.

Good morning, Professor Dr. Kamal, I hope you are well today.

from Greetings and a Meeting in the Realm of Knowledge

Qalat li-zamiliha Umar: Sabah al-Khayr ya Ustad!

She said to her colleague Omar: "Good morning, Professor!"

from Morning Greetings at the University