The word undiscipline 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: 23
Highest Scoring Words With Friends™ Play In The Letters undiscipline
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Seven Letter Word Alert: (29 words)
cuisine, incised, incline, include, indices, induces, inlines, insipid, insulin, inulins, lindens, lineups, lipidic, lupines, nuclide, pencils, pinnule, sluiced, spicule, spindle, spinule, splenic, spliced, splined, suicide, unclips, undines, unipeds, unlined