The word substantives 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: 21
Highest Scoring Words With Friends™ Plays In The Letters substantives
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Seven Letter Word Alert: (45 words)
absents, abusive, assents, attunes, aunties, autists, bassets, bassist, battens, biasses, bitsets, busiest, butanes, butties, instate, invests, naivest, natives, seitans, sestina, siestas, sinuate, sinuses, situate, statins, stative, statues, suavest, subnets, subsets, subsist, subsite, subtest, subvein, subvent, sunsets, sustain, tabinet, tautens, tetanus, tissues, unbaits, unseats, vainest, vastest