The word diminutiveness is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 25
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (70 words)
deities, dements, demises, demists, densest, dentine, dentins, destine, detinue, detunes, deveins, devests, devises, dieties, dietine, diimine, dimness, dissent, divests, divines, dunites, dustmen, eminent, endives, ensuite, evident, imidine, indents, indites, indiums, insides, intends, intense, invents, invests, invited, invitee, invites, itemise, mindset, minuets, minuses, minutes, misedit, missuit, mistune, misused, munited, munites, nemesis, nudists, nutseed, seitens, sestine, siemens, snidest, stimied, stimies, studies, stunned, sunnies, tediums, tissued, undents, undines, unities, unmined, untimed, uveitis, visited