The phrase "a stringent" is correct and can be used in written English.
It means something that is strict or severe. Example: The company's policies were a stringent set of rules that all employees had to follow.
Of course this is a stringent view.
They devised a stringent "all work test".
There is a stringent licensing system for diggers.
Also, SAC has protected itself with a stringent redemption policy.
Carmakers acknowledge that they can comply with a stringent standard.
"There's not a stringent process, not even providing proof that you're affiliated with the brand.
As she applies a stringent moral code in her novels, so she does in real life.
The program requires passing a stringent entrance exam, and proficiency in three languages.
I imagine a stringent and superior sculptor like Judd would be appalled.
The Hornets pounded the Nets on the boards and with a stringent zone defense.
It should establish a stringent system to ensure compliance and demand that top management be replaced.
