The word complementing 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: 30
Highest Scoring Words With Friends™ Plays In The Letters complementing
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Seven Letter Word Alert: (42 words)
clement, cloning, comment, compete, compile, eloping, eminent, emoting, epitome, genetic, genomic, gentile, lection, lemming, lenient, linemen, meeting, melting, memento, memetic, mention, miocene, mitogen, molting, neglect, nepotic, nominee, nonepic, onetime, opening, peeling, pelting, penlite, petiole, pigment, pimento, polemic, pontine, teeming, telecom, telogen, topline