The word nethermost 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: (25 words)
emoters, estrone, heteros, hornets, mentors, meronts, meteors, monster, mothers, netters, rehomes, rehones, remotes, rosette, shorten, smother, snotter, tenters, tethers, theorem, thereon, thereto, thermos, thrones, torment