Just pretend to sing

• Audio and video alignment of speech
• Linking of speaker's mouth movements and voice in filmed recordings
• Heard aboard loose ships making slogan for mime
• Mouth the lyrics
• "Sing" without singing
• Fake it, musically
• Sing along silently
• Fake it, in a way
• Pretend, in a way

Wiktionary Word definitions in Wiktionary
n. (alternative spelling of lip sync English) vb. (alternative spelling of lip-sync English)