Simple past tense and past participle of lip-sync.(verb)
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Use "lip-synced" in a sentence
"Rapper M.I.A.'s 1.5 seconds of a middle finger, raised pseudo-defiantly during Madonna's completely ridiculous, lip-synced Super Bowl halftime show."
"For decades, drag queens have dressed up as superstars and lip-synced to hit songs."
"She impulsively changed outfits in nightclubs, hung out with shady guys with names like Osama and Adnan, and listlessly lip-synced her way through a live performance on MTV."