1.to not tell someone something, or to not show how you feel
2.to not move toward someone or something, or to stop someone from doing this
3.to prevent someone from making progress
4.to keep part of something so that you can use it later
5.if you keep back laughter or tears, you stop yourself from laughing or crying
6.to keep part of an amount of money that belongs to someone or is owed to them
keeps back