The word polyphosphate is playable in Words With Friends™, but 1 blank substituting for the letter 'p' is 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: 25
Highest Scoring Words With Friends™ Plays In The Letters polyphosphate
:
Seven Letter Word Alert: (21 words)
apostle, applets, hatshop, healths, healthy, hopples, laptops, loathes, oophyte, ooplast, papoose, phthaly, polyose, pothole, shapely, soothly, spyhole, taphole, teashop, topples, toyshop