The word underestimating 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
Seven Letter Word Alert: (571 words)
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reaudit, redates, reedits, reemits, regains, regents, regimen, regimes, regnant, reguide, reigned, reimage, reining, remains, remands, remated, remates, remends, remiges, reminds, remined, remines, remints, remnant, renamed, renames, rending, rennets, renting, residue, restage, restain, restate, resting, resumed, retains, retaste, reteams, retimed, retimes, retinas, retints, retuned, retunes, reunite, reusing, ridings, ringman, ringmen, rinsing, rudites, ruining, runtime, rusting, rutting, sainted, sandier, sanding, sandmen, sardine, saunter, sauteed, seamier, seaming, searing, seating, sedater, sedgier, seeding, seeming, segment, seminar, sending, seriate, seriema, setting, sidearm, sideman, sigmate, sinuate, siriema, sirname, sitting, situate, smarted, smarten, smartie, smatter, smeared, smidgen, smidgin, smiting, smitten, smudger, smutted, snaring, stadium, stagier, stained, stainer, standee, stander, stannum, staring, started, stating, statued, stature, steamed, steamer, stented, sterane, sterned, sternum, stimied, stinger, stinted, straint, strange, stratum, striate, student, studier, stunned, stunner, stunted, stunter, sugared, suiting, sunnier, surname, tainted, tandems, tangent, tangier, tanners, tannest, tantrum, targets, tasered, tastier, tasting, taunted, taunter, tautens, tauting, teaming, tearing, teasing, teatime, tediums, teeming, tenants, tenders, tending, tenners, tensing, tentage, tenters, tentier, tenting, tenured, tenures, termini, termite, ternate, testier, testing, tetanus, tidiers, tidiest, tidings, tiering, timider, timings, tinders, tiniest, tinners, tinnier, tinters, tintier, tinting, tirades, tradein, trading, trained, trainee, transit, treated, treeing, triaene, triages, tridems, trident, trienes, tritium, truants, trudgen, trudges, trusted, trustee, tsunami, tundras, tunings, turning, unaimed, unaired, unarmed, undents, undines, undrest, uneager, unearnt, uneaten, uniters, unities, uniting, unmated, unmates, unmeant, unmerge, unmined, unnamed, unrated, unreset, unrisen, unsated, unstage, unstain, untamed, untimed, untired, untread, untried, uridine, urinate, uterine, uttered