The word ruthfulness 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 ruthfulness
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Seven Letter Word Alert: (28 words)
fluents, flusher, flushes, fluster, fluters, furless, futures, hunters, hurtful, hurtles, hustles, lushest, lusters, reflush, restful, results, rustles, ruthful, shunter, sleuths, slusher, sulfurs, sutlers, sutures, tuneful, unfurls, unrests, urnfuls