The word mechanists 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™ Play In The Letters
Seven Letter Word Alert: (37 words)
achiest, aitches, amnesic, anthems, ascents, ascites, ashiest, atheism, caseins, chaises, chasten, chemist, cinemas, ethnics, haemins, hastens, icemans, icemass, incests, inmates, inseams, insects, machine, matches, messiah, miscast, misseat, nematic, sachets, scathes, schemas, secants, seitans, sestina, stamens, stances, theisms