The word peristyle 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: 15
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (25 words)
epistle, eyepits, eyeslit, pelites, pelters, perlite, petrels, pyrites, repiles, replies, reptile, respelt, respite, resplit, restyle, retiles, retypes, steeply, sterile, stripey, stylier, tersely, triples, yelpers, yperite