Illustration of mastiff
: any of a breed of very large massive powerful smooth-coated dogs that are apricot, fawn, or brindle and are often used as guard dogs
Examples of mastiff in a Sentence
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Spanish mastiffs, meanwhile, are also known for being hugely affectionate towards family, and a fierce defender of livestock as a working dog.
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John W. Dean, MSNBC Newsweek, 7 Apr. 2025
Anthony Devlin / Getty Images Miuccia emerged victorious, beating Ana, a Jack Russell terrier; Liza, the miniature schnauzer; Viking, the Tibetan mastiff; Shake, the Australian shepherd; Sophia, the papillon; and Suzie, the cocker spaniel.
—Mithil Aggarwal, NBC News, 10 Mar. 2025
Those breeds include the Bernese mountain dog and mastiffs.
—Krystal Nurse, USA TODAY, 21 Feb. 2025
First-round competitor Brina, for instance, is a 158-pound (71.6 kilogram) Neapolitan mastiff.
—Jennifer Peltz, Chicago Tribune, 12 Feb. 2025
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John W. Dean, MSNBC Newsweek, 7 Apr. 2025
Anthony Devlin / Getty Images Miuccia emerged victorious, beating Ana, a Jack Russell terrier; Liza, the miniature schnauzer; Viking, the Tibetan mastiff; Shake, the Australian shepherd; Sophia, the papillon; and Suzie, the cocker spaniel.
—Mithil Aggarwal, NBC News, 10 Mar. 2025
Those breeds include the Bernese mountain dog and mastiffs.
—Krystal Nurse, USA TODAY, 21 Feb. 2025
First-round competitor Brina, for instance, is a 158-pound (71.6 kilogram) Neapolitan mastiff.
—Jennifer Peltz, Chicago Tribune, 12 Feb. 2025
See All Example Sentences for mastiff
Cite this Entry
“Mastiff.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/mastiff. Accessed 16 Apr. 2025.
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mastiff
noun
mas·tiff
ˈmas-təf 
: any of a breed of large powerful smooth-coated dogs often used as watchdogs and guard dogs
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