white hat

noun

1
: one who is admirable and honorable
2
: a mark or symbol of goodness
… could use a few more guys in white hats.Robert Christgau
3
: a hacker who tests computer systems for possible vulnerabilities so that they can be fixed
These so-called "white hats" will spend days or weeks searching company systems to come up with recommendations for fortifying corporations against … threats.Greg Wiles
compare black hat

Word History

Etymology

from the white hats stereotypically worn by law-abiding characters in movie westerns

First Known Use

1965, in the meaning defined at sense 1

Time Traveler
The first known use of white hat was in 1965

Browse Nearby Words

Cite this Entry

“White hat.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/white%20hat. Accessed 7 Nov. 2025.

Last Updated: - Definition revised
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!