Is “Mastiff” a Scrabble word?
Yes
MASTIFF
Valid in at least one Scrabble dictionary
Valid in these dictionaries
SOWPODS / CSW
Scrabble UK & International
TWL / NWL
Scrabble North America
Large English Dictionary
General English word list
Meaning of Mastiff
/ˈmæstɪf/
noun
1.One of an old breed of powerful, deep-chested, and smooth-coated dogs, used chiefly as watchdogs and guard dogs.