The word tediousness 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: 14
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (29 words)
denoise, denotes, densest, desists, destine, detinue, detunes, dissent, dunites, ensuite, nosiest, nudists, nutseed, osseins, outsees, outside, seitens, session, sestine, sinuses, snidest, snouted, stenose, studies, studios, sunsets, tedious, tissued, tissues