Is “Firmest” a Scrabble word?
Yes
FIRMEST
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 Firmest
adjective
1.Steadfast, secure, solid (in position)
“It's good to have a firm grip when shaking hands.”
2.Fixed (in opinion)
“He was firm that selling his company would a good choice and didn't let anyone talk him out of it.”
3.Durable, rigid (material state)
“firm flesh; firm muscles, firm wood; firm land (i.e. not soft and marshy)”