Sing silently, in a way

• Sing along silently
• Audio and video alignment of speech
• Mouth the words to a recorded song: Hyph
• Pretend, in a way
• Go through the motions in a music video?
• Drag show performance
• Mouth, in a way
• Mouth the lyrics
• "Sing" without singing

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