The word bestriding 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: (33 words)
bedirts, besting, bestrid, binders, bingers, birdies, birding, bitings, bitsier, bridges, dieting, dingier, dingies, dirties, ditsier, ebriids, editing, ignited, igniter, ignites, inbreds, inditer, indites, insider, nitride, rebinds, resting, ridings, stinger, tidiers, tidings, tiering, tinders