The word decolourizing 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: 31
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (65 words)
ceiling, clinger, codling, coiling, cologne, condole, cooling, cording, coreign, corndog, cringed, crinoid, croodle, crooned, crunode, curling, decolor, deicing, dilogun, dingier, dooring, dueling, dulcing, educing, eliding, eluding, eroding, gloried, gluonic, godlier, groined, guerdon, guilder, iconize, idolize, ignored, include, inducer, indulge, inuloid, iodizer, ionized, ionizer, lionize, loonier, lounged, lounger, negroid, nuclide, odorize, ozonide, redoing, regulon, reicing, roiling, roundel, uncored, undergo, unoiled, uridine, zeroing, zincier, zincode, zincoid, zingier