The word oppositeness 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: 19
Highest Scoring Words With Friends™ Play In The Letters oppositeness
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Seven Letter Word Alert: (38 words)
epitope, insteps, isotope, nosiest, onestep, openest, opposes, options, osseins, osteons, penises, pentose, peonies, pepsins, peptise, peptone, pisspot, pistons, poesies, poetess, poetise, poisons, possets, poteens, potions, potpies, seitens, session, sestine, snippet, soonest, spinets, spinose, stenose, steppes, stepson, toonies, topspin