The word childlessness 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
Seven Letter Word Alert: (21 words)
chilled, chisels, deciles, decline, dehisce, diesels, endless, helices, iceless, illness, lessens, license, lichens, lidless, linseed, sessile, shelled, shields, shilled, silence, sinless