The word matronymics 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: 23
Highest Scoring Words With Friends™ Play In The Letters matronymics
:
Seven Letter Word Alert: (30 words)
acronym, actions, ammonic, atomics, atomism, atonics, cantors, cartons, cations, citrons, commits, cratons, crayons, crimson, cystoma, cytomas, ironyms, marconi, marmots, martins, masonic, masonry, matrons, microns, myotics, rations, somatic, trionym, trisomy, tyromas