The phrase "daunting subject" is correct and usable in written English
It is often used to describe a topic that is complex, or difficult to understand. For example, "Tax law is a daunting subject for most people, but it is essential to understand the basics."
This is a massive, daunting subject, and I did not know where it would take me.
Besides the seemingly daunting subject matter, there's the difficulty of form to deal with.
I was abroad last semester, but even if I had been at Harvard the daunting subject of post-grad plans would have been exhausting.
This can be a result of wrestling with a daunting subject and not being up to its demands.
The museum that had the audacity to take the measure of the whole universe with its new planetarium has now turned its attention to another daunting subject: the remote and forbidding Gobi Desert of Mongolia.
That humanity nearly takes the form of bodice-ripping ("The man in me knew that we were alone, and the man in me knew that I could have this woman"), now that Ms. Rice's confidence about her daunting subject allows some of her familiar proclivities to emerge.
Drake remembers the moment when the fate of the twin towers on 9/11 came into focus as their subject: "suddenly it was undeniable, and once we realised that could be the subject – daunting as it is – we could not say no".
His in-tray contains three subjects daunting even for a minister famed for his reforming zeal: courts, prisons and human rights.
The complexity of the subject is daunting.
In the course of reaching that conclusion, Jenkins proves equal to the daunting scale of his subject, a Toscanini for Beethoven.
This is all the more remarkable since, as here, their subjects include daunting sites, such as a kindergarten, theatre and swimming pool abandoned as the Chernobyl nuclear disaster struck.
