The word protuberant 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: 19
Highest Scoring Words With Friends™ Plays In The Letters
Seven Letter Word Alert: (25 words)
abettor, aborter, abutter, baronet, operant, ornater, outearn, outrant, outrate, partner, pattern, perturb, portent, praetor, probate, pronate, prorate, protean, protura, rapture, taunter, torrent, torture, trouper, tutorer