Is “Shellback” a Scrabble word?
Yes
SHELLBACK
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 Shellback
noun
1.A worldly sailor.
2.A sailor who has crossed the equator.
Synonyms: barnacle