be in tune
1. To have the proper musical pitch. People don't realize how hard it is to be in tune when you can't hear yourself singing!
2. To be in agreement with someone or something. I'm sure she feels the same way I do because we're always in tune.
be out of tune
1. To lack the proper musical pitch. People don't realize how easy it is to be out of tune when you can't hear yourself singing.
2. To be in disagreement with someone or something. I'm often out of tune with my family because they don't approve of my line of work.