"challenging moment" is a correct and usable phrase in written English. You can use it to refer to a specific moment or time that is difficult or hard to manage. For example, "I'm currently going through a challenging moment in my life, but I'm determined to keep going."
There, another challenging moment arose.
"It is heartening for everyone involved with the organisation in this extremely challenging moment," he added.
Tell us about a challenging moment on set, perhaps a light bulb moment.
The nonprofit group picked a challenging moment to rejuvenate Christmas Seals.
No one disputes that this is a unique and challenging moment in our history.
His most challenging moment surely came this season with A. J.'s suicide attempt.
The more challenging moments have come off the field.
At particularly challenging moments, remember that this witch brought your beloved into the world.
Were there any especially challenging moments while you were writing Lady Midnight?
But they are not the only ones saying Spain faces one of its most challenging moments in recent history.
Although I have had challenging moments, I have not self-harmed once since coming back and I am approaching a year free of self-harm altogether.
I love the desktop app, it’s always running on my Mac. Ludwig is the best English buddy, it answers my 100 queries per day and stays cool.
Cristina Valenza
Retail Lead Linguist @ Apple Inc.