The word repentantly 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: 19
Highest Scoring Words With Friends™ Plays In The Letters
Seven Letter Word Alert: (27 words)
aplenty, enteral, entrant, entreat, eternal, lantern, palette, pattern, peltate, penalty, pentane, pentyne, planner, planter, platter, plenary, prattle, prelate, prelaty, pteryla, repanel, replane, replant, replate, repleat, tannery, ternate