The word lamplighter 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: 23
Highest Scoring Words With Friends™ Plays In The Letters
Seven Letter Word Alert: (29 words)
alltime, alright, epigram, glamper, haplite, harelip, impaler, lamplit, lempira, lighter, literal, maltier, marlite, megahit, migrate, palmier, philter, philtra, philtre, pillage, primate, ragtime, relight, replait, tallier, thermal, tillage, tramell, trample