re·frac·to·ry
ri-ˈfrak-t(ə-)rē 
1
: resisting control or authority : stubborn, unmanageable
2
a
: resistant to treatment or cure
a refractory lesion
b
: unresponsive to stimulus
c
: immune, insusceptible
after recovery they were refractory to infection
3
: difficult to fuse, corrode, or draw out
especially
: capable of enduring high temperature
plural refractories
: a refractory person or thing
especially
: a heat-resisting ceramic material
Did you know?
Refractory is from the Latin word refractarius. During the 17th century, it was sometimes spelled as refractary, but that spelling, though more in keeping with its Latin parent, had fallen out of use by the century's end. Refractarius, like refractory, is the result of a slight variation in spelling. It stems from the Latin verb refragari, meaning "to oppose."
Examples of refractory in a Sentence
Adjective
refractory players will be ejected from the game
believing that rules are only for other people, he's been refractory virtually his entire life
Recent Examples on the Web
Erik Kobayashi-Solomon, Forbes.com, 7 Aug. 2025
This is due to a rare condition called refractory celiac disease, which requires specialized treatment.
—Daryl Austin, USA Today, 19 July 2025
IEEE Spectrum, 30 Oct. 2025
Ideally, engineers would use refractory metals like tungsten, molybdenum, and chromium.
—Mrigakshi Dixit, Interesting Engineering, 10 Oct. 2025
See All Example Sentences for refractory
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Adjective
This is, by far, the most common TES approach in industry, with most companies using legacy technologies like refractory bricks and molten salt to store heat in insulated shipping containers.
—Erik Kobayashi-Solomon, Forbes.com, 7 Aug. 2025
This is due to a rare condition called refractory celiac disease, which requires specialized treatment.
—Daryl Austin, USA Today, 19 July 2025
Noun
These warm hundreds of tonnes of refractory bricks to temperatures up to 1,500 °C.
—IEEE Spectrum, 30 Oct. 2025
Ideally, engineers would use refractory metals like tungsten, molybdenum, and chromium.
—Mrigakshi Dixit, Interesting Engineering, 10 Oct. 2025
See All Example Sentences for refractory
Cite this Entry
“Refractory.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/refractory. Accessed 4 Nov. 2025.
Copy CitationMedical Definition
refractory
adjective
re·frac·to·ry
ri-ˈfrak-t(ə-)rē
1
: resistant to treatment or cure
a refractory fulminant lesion
had disease that was extremely refractory to multiple intensive therapies—Michelle L. Bennett et al.
Michelle L. Bennett et al.2
: unresponsive to stimulus
the refractory period of a muscle fiber
3
: resistant or not responding to an infectious agent : immune
refractory to reinfection
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