The word centerlines 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: 17
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (40 words)
centers, centres, cistern, clients, cretins, eeriest, enteric, enticer, entices, entrees, entries, incense, intense, interns, lectern, lenient, lenites, license, linnets, nitrene, recites, recline, reelect, relents, relines, rennets, reslice, retiles, scenter, secrete, silence, sincere, steelie, stencil, sterile, teenier, tenners, tensile, tinners, trienes