The word thrombosing 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: 22
Highest Scoring Words With Friends™ Plays In The Letters thrombosing
:
Seven Letter Word Alert: (29 words)
bighorn, bigshot, booming, boorish, booting, borings, brights, gnomish, gnomist, gothism, hooting, horsing, hosting, monitor, mooring, moorish, mooting, motions, rooming, rooting, shooing, shoring, sooting, sorting, storing, thrombi, throngs, tombing, torsion