The word prospector 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: 19
Highest Scoring Words With Friends™ Play In The Letters prospector
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Seven Letter Word Alert: (23 words)
coppers, cropper, opposer, poopers, poorest, porters, presort, proctor, propose, prosper, rectors, reports, reroots, rooster, rooters, scooper, scooter, stooper, stopper, toppers, toprope, torpors, trooper