The phrase "a dangerous competitor" is correct and usable in written English.
It can be used to describe someone or something that poses a significant threat in a competitive context, such as business or sports.
Example: "In the upcoming tournament, we need to prepare for our opponent, who is known to be a dangerous competitor."
Alternatives: "a formidable rival" or "a serious contender".
After all, it's only a quarter-point rise, in a faraway country that doesn't interest most Americans now that it no longer seems a dangerous competitor.
Most residents ignore Majid in his stained threadbare clothes, assuming he is a drug addict, but those in the local garbage collection fold consider him an outlaw and a dangerous competitor.
Insurers saw the state as a dangerous competitor in the market for security, and took great strides (through advertising, public relations campaigns, and extensive lobbying) to convince Americans to turn away from the idea of a providential state, and to instead embrace privatized security.
If Facebook gets serious about file sharing it could become a dangerous competitor to Dropbox.
It passed up early opportunities to buy Platinum Technology, now a dangerous competitor, and Boole & Babbage, which it finally bought last year for $900 million in stock.
While traditional in-person eye exam places might see Opternative as a dangerous competitor right now, the startup hopes to partner with them down the line.
In the eighties, of course, the environmental aspect of SodaStream's business didn't have the force it does now; that angle has given the company a new raison d'etre, and makes it a more dangerous competitor.
And competitors in the funding ecosystem who write off crowdfunding as a dangerous rival do so at their peril.
Stephen Snedden plays Jimmy Bond, a handsome lunk who is the brawn to their brains, and Zuleikha Robinson is Yves Adele Harlow, a beautiful and dangerous competitor.
Weinberg's non-ambitious goals make him a particularly odd and dangerous competitor online.
But hawks in the Pentagon and conservatives in Congress, who view China as an ambitious and potentially dangerous competitor in the Pacific, have been uneasy about the improving relations.
