The word gravitationally 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: 26
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (53 words)
agility, allying, analogy, angrily, aviator, gallant, glottal, gorilla, granola, gravity, ignitor, intagli, invitro, lairing, lilting, nattily, olivary, orating, ovarian, railing, rattail, ratting, ravioli, rioting, roiling, rolling, rotting, tailing, tilling, tilting, toiling, tolling, tonally, totally, travail, trilogy, trinity, trivial, vaginal, vagrant, valiant, vanilla, variant, variola, varying, vatting, vialing, villain, violing, virally, vitally, vitriol, yatagan