The word waitressed 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: 14
Highest Scoring Words With Friends™ Plays In The Letters
Seven Letter Word Alert: (48 words)
aeriest, aridest, astride, dearest, dearies, deserts, desires, dessert, dewater, dewiest, dewires, diester, dieters, disease, disrate, easiest, readies, reasted, redates, reedits, resawed, reseats, resides, satires, seaside, seaters, sedater, sedates, seriate, steward, strawed, strewed, strides, sweated, sweater, tarweed, tasered, teasers, tirades, tressed, waisted, waiters, wariest, wasters, watered, wearied, wearies, wrested