This is a complimentary or promotional term or phrase without any attribution. For example:
Accomplished actress, Tara Reid…
The word “accomplished” has no attribution, therefore it’s considered “puffery” or “peacocking.”
(Also, with Tara Reid, it’s highly debatable. If the subject was Meryl Strep, would it be as obvious? I’m not sure.)
Some examples from an article about writing:
- one of the most important
- one of the best
- a well-known
- the indisputable
- an iconic
- the legendary
- immensely
- one of the greatest
- outstanding
- a world-class
- most respected
- among the most notable
Wikipedia lists the following as some “words to watch”:
legendary, best, great, acclaimed, iconic, visionary, outstanding, leading, celebrated, popular, award-winning, landmark, cutting-edge, innovative, revolutionary, extraordinary, brilliant, hit, famous, renowned, remarkable, prestigious, world-class, respected, notable, virtuoso, honorable, awesome, unique, pioneering, phenomenal
The phrase “peacock term” might actually be an invention of Wikipedia, which is where I encountered the phrase. It’s mentioned on the internal page linked above. I can’t find when that reference was added, but I did find a template page that was created in October 2008.
This roughly coincides with Google Trends data which shows usage of the word starting earlier in 2008. It’s possible that the phrase started being used by Wikipedia editors to describe a writing style, then became so ingrained that they codified it in a template.