Is “Whomsoever” a Scrabble word?
Yes
WHOMSOEVER
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 Whomsoever
/ˌhumsoʊˈɛvəɹ/
pronoun
1.Whatever person or persons (as object of a verb or preposition): emphasised or elaborated form of whomever.
“We shall tell the good news to whomsoever we meet.”