mastiff

American

[mas-tif, mah-stif] / ˈmæs tɪf, ˈmɑ stɪf /

noun

one of a breed of large, powerful, short-haired dogs having an apricot, fawn, or brindled coat.

mastiff British

/ ˈmæstɪf /

noun

an old breed of large powerful short-haired dog, usually fawn or brindle with a dark mask

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of mastiff

1300–50; Middle English mastif, perhaps extracted from Anglo-French masti ( n ) s (taken as *mastifs ), plural of Old French mastin < Vulgar Latin ( canis ) *ma ( n ) suētīnus, derivative of Latin mansuētus tame, mild ( see mansuetude)

Compare meaning

How does mastiff compare to similar and commonly confused words? Explore the most common comparisons:

mastiff vs. bullmastiff

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

They joked about sending their mastiff to the door next time.

From Salon • Jun. 8, 2025

Previously, the Lowe family had a bull mastiff rescue, Gus, who bit son Samuel in 2023 after the boy tried to bend down and pet him.

From Los Angeles Times • Mar. 19, 2025

We were sitting in his studio while Kaya, his enormous Tibetan mastiff, weaved through our legs.

From Slate • Feb. 18, 2025

James Strauch, 42, said he eventually started offering landlords £1,000 deposit to let him rent with his four-year-old labrador mastiff cross, Bruno.

From BBC • Oct. 9, 2024

Stannis Baratheon with a grievance was like a mastiff with a bone; he gnawed it down to splinters.

From "A Dance with Dragons" by George R. R. Martin

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023