The word impracticability cannot be made in Words With Friends™. It is 16 letters long, too long to fit on a WordsWithFriends board (15 letters max).
Highest Scoring Words With Friends™ Plays In The Letters impracticability
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Seven Letter Word Alert: (38 words)
ability, acclaim, acrylic, airmail, airplay, albitic, amiably, aplitic, biliary, bitpart, caltrap, cambial, cambric, campily, capably, capital, cattail, cattily, ciliary, clarity, clipart, cryptic, mailcar, marital, martial, militar, militia, partial, patrial, playact, practic, primacy, pyritic, rattail, tacitly, tilapia, tipcart, typical