The word grumpiness 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: 20
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (34 words)
impress, impugns, ingress, insures, messing, minuses, mispens, misuser, mungers, musings, perming, pingers, premiss, purines, pursing, pussier, resigns, respins, reusing, rumping, signers, simpers, singers, snipers, springs, spumier, spuming, spurges, sunrise, surmise, suspire, umpires, uprisen, uprises