The word reenforcing 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: 21
Highest Scoring Words With Friends™ Plays In The Letters
Seven Letter Word Alert: (23 words)
confine, conifer, coreign, cornier, corning, cringer, enforce, feigner, fencing, fiercer, forcing, foreign, freeing, fringer, generic, grinner, inferno, nonfire, nonfree, reefing, refiner, reforge, reigner