The word platitudinarian 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 platitudinarian
:
Seven Letter Word Alert: (21 words)
annular, diptail, diurnal, initial, lunaria, natural, nuptial, partial, patrial, pintail, plantar, plaudit, puritan, radiant, rattail, tailpin, tapirid, tartpan, tilapia, titular, triptan