3)a version of lip movement in which a recorded version of a song is being played and a self-described "artist" moves their mouth to the words being sung, stimutaneously dancing in a choegraphed fashion.
4)Fake talent. Also known as acid reflux.
2)She may have acid reflux, but she can sure do a great hoedown.
3)"And here we have Hilary Duff lip-syncing while looking into a mirror, which serves as the rigerous rehersal for her next tour..."
4)"Hey man, she couldn't sing so she had a right to lip sync! It says so in the rules...."