The phrase 'formidable impediment' is correct and usable in written English.
You can use it to describe an obstacle that will be difficult to overcome. For example, "The formidable impediment of budget constraints has made it difficult for the company to move forward with the project."
What's more, today formidable impediments remain to achieving this dream--specifically, the adoption of common, industry-wide standards.
India - hamstrung by post-Pokharan II sanctions that were formidable impediments to its economic growth and strategic ambitions - seized on the American overture, thus ending the long estrangement and ushering "Achhe Din".
Although high throughput technology has been democratized, formidable impediments remain that prohibit researchers whose work is not in human, model human, or agriculturally important species from realizing its benefits.
Conservatives will not be able to understand the elusive nature of Obamaism and counter its formidable appeal until they remove the impediment of their own insular, rigid ideology.
While the political impediments to action remain formidable, the government could quickly do a great deal to add paychecks and restore vigor to the economy.
Branch workers around the country described to me a feeling during this period that they were being kept out on the shop floor as a hindrance, but no real impediment, to incident; on display like scarecrows, and about as formidable a deterrent.
The report found that the center's planning arm struggled with "systemic impediments" like overlapping statutes, culture clashes with different agencies and tensions with two formidable players: the State Department's counterterrorism office and the C.I.A.
The slight speech impediment.
Parents are an impediment.
