The word efflorescing 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: 25
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (84 words)
clinger, cloners, closing, coffees, coffers, coffins, coffles, cognise, coiners, confers, conifer, coreign, creoles, cringes, cronies, elogies, eloigns, enclose, encores, enforce, feeling, feesing, feigner, felines, fencers, fingers, fleeing, flenser, florins, forcing, foreign, foreleg, forelie, forseen, freeing, fringes, frolics, generic, girnels, glories, golfers, goniffs, greisen, icefloe, ignores, leering, legions, license, lingers, lingoes, necrose, negroes, offence, offense, officer, offices, offline, olefins, oneself, recline, reclogs, reclone, reclose, recoils, recoins, reefing, reeling, reffing, refiles, refines, reflies, reflogs, regions, reliefs, relines, reslice, scoffer, scoring, signoff, silence, sincere, slinger, sniffer, sniffle