The word feudatories 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: 16
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (74 words)
aeriest, aridest, aroused, astride, astroid, auditee, auditor, austere, deafest, dearest, dearies, defeats, defiers, defrost, defuser, detours, diester, dieters, disrate, draftee, dustier, editors, erotise, erudite, etaerio, euaster, fadeout, faeries, fairest, feasted, feature, fedoras, foisted, foister, forties, freesia, frosted, fruited, furoate, ioduret, outdare, outfire, outread, outride, outside, readies, readout, reasted, reaudit, redates, reedits, refused, refuted, refutes, residue, roadies, roasted, roisted, roseate, rudites, sauteed, sedater, seriate, sortied, steroid, storied, stourie, studier, surfeit, tasered, tedious, tierods, tirades, urostea