The word grandmother 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: 20
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (32 words)
adorner, another, armored, dormant, dragnet, garment, gnarred, grander, granted, granter, groaned, groaner, hagrode, hoarder, homaged, magneto, megaton, menorah, montage, mordant, mordent, norther, oranger, ornater, readorn, regrant, roadmen, tangoed, thonged, thorned, throned, tonearm