The word sharpeners 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: 16
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (40 words)
arsheen, asperse, earners, ensears, erasers, harness, harpers, heapers, hearers, hearses, parsers, phraser, phrases, presser, rashers, raspers, reapers, reheaps, rehears, reparse, repress, rerapes, reshape, reshare, resnaps, respans, serapes, seraphs, shapers, sharers, sharpen, sharper, shearer, sherpas, snarers, sparers, sparser, spearer, sphenes, spheres