The word vapourousness 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: 23
Highest Scoring Words With Friends™ Plays In The Letters
Seven Letter Word Alert: (32 words)
arouses, assures, nervous, noosers, nouveau, onerous, operons, osseous, parsons, passers, persona, persons, poroses, poseurs, pursues, reasons, resnaps, respans, savours, seasons, sensors, snooper, soapers, sooners, soprano, soursop, sponsor, spouses, surpass, unparse, uprouse, vapours