The word plessimeter 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: 18
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (78 words)
eeriest, emerses, empires, empress, emptier, empties, epimers, epistle, esteems, impress, limpest, limpets, lispers, meeters, melters, messier, metrise, misstep, misters, peelers, pelites, pelters, perlite, permits, persist, pesters, pestles, petless, petrels, pieless, pitless, preemie, prelims, premeet, premelt, premise, premiss, presets, priests, reemits, relists, remeets, remelts, repeels, repiles, replete, replies, reptile, resmelt, respelt, respite, resplit, restems, resteps, retiles, retimes, rimless, seepier, simpers, simpler, simples, sleeper, smelter, smilers, smiters, spriest, sprites, steelie, steeper, steeple, sterile, stripes, teemers, tempers, temples, tieless, tipless, triples