The word speleologists 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™ Play In The Letters speleologists
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Seven Letter Word Alert: (49 words)
egoists, egoless, elegist, elegits, ellipse, elogies, elogist, epilogs, epistle, glioses, glosses, gooiest, goosies, gospels, gossips, isotope, legless, lipless, loosest, oolites, osselet, pegless, pelites, pellets, pestles, petiole, petless, pieless, piglets, pistols, pitless, poesies, poetess, poetise, possets, postils, sessile, soloist, spiegel, spigots, stogies, stooges, stoolie, tellies, tieless, tipless, toeless, topless, topsoil