The word changeableness 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: 27
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (40 words)
abashes, absence, achenes, ageless, anneals, bagless, balance, baleens, bangles, banshee, beaches, beagles, beeches, belches, benches, beseech, changes, channel, cheeses, clashes, cleanse, enables, encases, enhance, enseals, essence, galenas, geneses, glances, gnashes, hasbeen, lasagne, leaches, leashes, leeches, nabales, scalene, seabags, seances, seeable