The word lastingness 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: 16
Highest Scoring Words With Friends™ Plays In The Letters
Seven Letter Word Alert: (56 words)
aiglets, anglist, antigen, assents, assigns, elastin, elating, enlists, ensigns, entails, gasless, gelatin, genials, genital, gentian, glasses, glisten, ingests, lassies, lasting, leaning, leasing, lensing, ligases, ligates, linnets, listens, nailset, nesting, sagiest, salient, salines, salting, sassing, sealing, seating, seitans, sensing, sestina, siennas, siestas, signals, signets, silanes, silents, singles, singlet, sinless, slating, tagline, tangles, tassels, teasing, tensing, tingles, tinsels