The word parathyroids 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: 20
Highest Scoring Words With Friends™ Plays In The Letters parathyroids
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Seven Letter Word Alert: (34 words)
adaptor, airdrop, airdrys, airport, ariarys, ashtray, astroid, atrophy, atropia, dashpot, daytrip, dryrots, hairdos, hardtop, harpist, history, hydrops, pariahs, parotid, parrots, paydirt, portray, radiary, raphids, raptors, satrapy, stridor, thyroid, toadish, topiary, torpids, tripods, typhads, typhoid