The word hamstringing 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: 23
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (52 words)
airings, animist, arising, gaining, gaiting, garnish, gashing, gastrin, gingham, girning, grating, griming, hanging, harming, hinging, hinting, imaging, ingrain, insight, mannish, margins, martini, martins, mashing, matings, migrant, minting, misting, raining, raising, ranging, ranting, ratings, ringgit, ringing, ringman, rinsing, shaming, sharing, shining, sighing, signing, singing, smiting, snaring, staging, staring, tarnish, thiamin, tigrish, timings, tinging