The word estuarine 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: 11
Highest Scoring Words With Friends™ Play In The Letters estuarine
:
Seven Letter Word Alert: (33 words)
aeriest, antsier, arenite, aunties, austere, earnest, eastern, ensuite, entries, euaster, nastier, natures, nearest, neuters, nutsier, restain, retains, retinas, retunes, reunite, saunter, seriate, sinuate, stainer, sterane, tenures, trainee, triaene, trienes, uniters, unreset, urinate, uterine