The word vigilantism 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: 22
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (30 words)
aisling, anglist, animist, initial, intagli, lasting, listing, livings, mailing, maligns, malting, matings, militia, misting, sailing, salting, salving, silting, slating, slaving, sliming, smiling, smiting, staving, stiving, tailing, tilings, timings, vialing, vitamin