The word stairwells 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: 15
Highest Scoring Words With Friends™ Play In The Letters stairwells
:
Seven Letter Word Alert: (31 words)
airless, artless, lawless, literal, rallies, realist, relists, resails, retails, retills, rillets, sailers, saltier, satires, serials, slaters, slatier, stellar, stiller, swiller, tallier, tallies, tillers, trellis, wailers, waiters, wallets, wariest, warless, wasters, witless