"unique reason" is a correct and usable phrase in written English.
It can be used when describing something that is one of a kind or different from all others. Example: The unique reason for the company's success was their innovative marketing strategy.
Depending on where you are in your education and career, you might attend the career fair for a unique reason.
Javer, a Californian representing Britain, at least offered up a unique reason for her loss: "I practised for five hours a day, so I might have over-prepared".
As Ron Clarke, who of course had a unique reason to remember him fondly, put it: "There is not, and never was, a greater man than Emil Zatopek".
Our arguments and numerical experiments demonstrate that the inadequate dissipation associated to the shear wave may be a unique reason to cause the instability.
It was therefore concluded that a direct dissipation of the electrons provided by G. sulfurreducens could not be the unique reason of the changes in metabolic patterns.
Every one of them is coming for some unique reason, whether it's the latest and greatest music video or a YouTube original, or their favorite creators.
And while you have unique challenges of your own, you also have unique reasons to be hopeful.
But there are four unique reasons that this position is especially foreboding for ambitious apparatchiks, even Trump loyalists.
Consider your own unique reasons for pursuing a simultaneous degree and make the choice that suits you best.
Each person in our life has known us in a different context and for unique reasons, so each will define us slightly differently.
It took the firm's staff a full year to redesign the products to meet all these regulations, he laments.Moreover, high-tech lavatories succeeded in Japan for unique reasons.
