'Sync' is an abbreviation of 'synchronise'. To be out of sync with something or someone means that you are not in agreement, not matching or you are out of harmony. If two people or things are out of sync they are not moving or progressing at the same time as each other.

1. The team were badly out of sync with each other. They could barely string two passes together before they lost the ball and didn't manage a single shot on target all game.
2. I don't like watching dubbed movies because the movement of the lips and sound of the voice is often out of sync. I find it very distracting.

1. I was out of sync with the rest of the group because they all felt that we should focus our marketing campaign around TV adverts rather than social media.
2. The reason we're not getting anywhere with the project is because all our efforts are out of sync at the moment. We need to agree on a clear plan of action and then stick to it.

1. The CEO's ambitious expansion plans are totally out of sync with the reality of the economic situation the company currently finds itself in.