The word firelights 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: 18
Highest Scoring Words With Friends™ Play In The Letters
Seven Letter Word Alert: (25 words)
fighter, filters, firelit, fishier, flights, freight, frights, girlies, girlish, glister, gristle, lifters, lighter, relight, reshift, resight, shifter, sigfile, sighter, siltier, sleight, slither, stifler, tigrish, trifles