The word postmarking 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: 24
Highest Scoring Words With Friends™ Play In The Letters postmarking
:
Seven Letter Word Alert: (59 words)
agonism, agonist, amongst, armpits, gastrin, gnomist, imparts, impasto, imports, inkpots, inkspot, isogram, makings, margins, marking, martins, masking, matings, matrons, migrant, moating, orating, parings, parking, parsing, parting, pasting, patrons, porking, porting, posting, postman, prating, primost, rasping, ratings, rations, roaming, romping, signora, skating, smoking, soaking, soaping, soaring, sorting, sparing, sporing, staking, staring, stoking, storing, takings, tamping, tampons, tapings, tasking, toprims, troikas