The word northernmost 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 northernmost
:
Seven Letter Word Alert: (35 words)
honorer, hormone, hornets, mentors, meronts, monster, moorhen, mothers, mottoes, nonhero, norther, onshore, rehonor, reroots, reshoot, retorts, rhetors, roomers, rooster, rooters, rotters, shooter, shorten, shorter, smother, snorter, snotter, soother, thermos, thrones, tooters, torment, tornote, torrent, tremors