Is “Mouthbreather” a Scrabble word?
Yes
MOUTHBREATHER
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 Mouthbreather
noun
1.A person who routinely inhales and exhales through the mouth, instead of through the nose.
2.A person who is boorish, stupid, or otherwise unattractive.