The word colourlessness 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™ Play In The Letters colourlessness
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Seven Letter Word Alert: (58 words)
censers, censors, censure, cloners, closers, closure, colonel, colours, console, consuls, coolers, coulees, counsel, courses, creoles, creosol, cresols, cresses, crosses, cussers, enclose, encores, enrolls, ensouls, ensures, lessens, lessons, lessors, locules, loosens, necrose, noosers, onerous, osseous, reclone, reclose, recluse, recuses, rescues, resells, resoles, screens, scrolls, secerns, secures, sellers, sensors, sonless, sooners, sources, sucrose, sunless, unclose, uncross, unloose, unreels, unrolls, useless