The word featherless 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: (51 words)
artless, earless, elaters, falsest, falters, fathers, feather, feelers, festers, flasher, flashes, fleeter, fleshes, hafters, halters, hatless, healers, hearses, heaters, hefters, herself, lashers, lathers, leasers, leashes, leather, rashest, realest, reflash, reflate, reheats, reheels, relates, release, resales, reseals, reseats, sealers, seaters, seether, seethes, sheeter, shelter, slasher, slaters, slather, stealer, tealess, teasels, teasers, trashes