The word disincentive 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: 22
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (39 words)
deceits, deistic, deities, dentine, dentins, descent, destine, deveins, devices, diciest, dietics, dieties, dietine, divines, eidetic, endives, enticed, entices, evicted, evident, evinced, evinces, incense, incised, incited, incites, indents, indices, indicts, indites, intends, intense, invects, invents, invited, invitee, invites, scented, visited