The word happenstances 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: 26
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (44 words)
achenes, anapest, appease, aptness, ascents, aspects, canapes, canteen, capstan, caseate, catnaps, chasten, cheapen, encases, enchant, enhance, escapes, ethanes, happens, hastens, heptane, nascent, neatens, patches, peaches, peasant, pectens, penance, pencase, pentane, petnaps, phenate, sachets, saphena, sateens, scathes, seances, secants, senates, sensate, sphenes, stances, steppes, teaches