Alone; exclusively.
The word 'solely' is correct and usable in written English. You can use it to emphasize that something is the single factor or element in a situation. For example, "He was solely responsible for the success of the project.".
Chafee's candidacy seems targeted almost directly at Hillary Clinton and her foreign policy record – the Democratic equivalent of those conservative hawks who sought to enter the Republican primary solely to excoriate Rand Paul on the debate stage.
The authors say that the healthcare system cannot be solely blamed for this issue, which is strongly influenced by social and economic factors.
To make things worse, it was not a myth copied and perpetuated solely by the tabloids; the broadsheets were equally responsible for repeating it, and perhaps did more to legitimise it than the tabloids.
But the throng were autograph hunters of Robert Carlyle: they were only keen on pursuing the actor; I was alone in being solely interested in the director.
Instead of being organised solely on a geographic basis, the bank will now pool its expertise across sectors such as health, education and transport so that ideas could be shared across national borders.
Those managing the money are not guided solely by profit maximisation: there's an investment philosophy saying no money will be put into tobacco or Sudan.
Lucky for writers of children's fiction there are at least 10 opportunities for them to submit to prizes which are solely for fiction.
Being a terminologist, I care about word choice. Ludwig simply helps me pick the best words for any translation. Five stars!
Maria Pia Montoro
Terminologist and Q/A Analyst @ Translation Centre for the Bodies of the European Union