The word celebrator 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: 17
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (24 words)
abortee, aborter, alerter, bleater, bloater, caroler, caterer, cerebra, clearer, creator, earlobe, elector, erector, laborer, reactor, realter, realtor, rebater, rebrace, recrate, relater, retrace, terrace, treacle