The word harmfulness 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: 22
Highest Scoring Words With Friends™ Plays In The Letters
Seven Letter Word Alert: (43 words)
armfuls, armless, armsful, assumer, earfuls, femural, flamers, flasher, flashes, flusher, flushes, funeral, furanes, furless, harmful, harness, haulers, humaner, humeral, lashers, manless, manures, marshes, mashers, masseur, maulers, mensual, mushers, numeral, reflash, reflush, refusal, rumless, sensual, serumal, slasher, slusher, smasher, surname, unleash, unseals, unshare, unsmash