The word rigidification 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: 24
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (32 words)
adoring, angioid, carding, carotid, carting, coating, conidia, cording, crating, crinoid, darting, diction, dogcart, faction, fairing, fiction, forcing, frantic, idiotic, ignitor, indraft, infarct, ingraft, orating, organic, rafting, raiding, rifting, rioting, tracing, trading, triadic