The word flamethrower 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: 24
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (37 words)
alerter, armhole, farther, feather, felwort, femoral, floater, forearm, frother, leather, loather, rathole, realter, realtor, reflate, refloat, reframe, relater, remoter, rethrow, rewater, rewrote, telomer, theorem, thereof, thermal, thrower, trawler, waferer, waterer, weather, welfare, whereat, whereof, whereto, wolfram, wreathe